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WSL2-Linux-Kernel/drivers/md/dm-switch.c

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C
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dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
/*
* Copyright (C) 2010-2012 by Dell Inc. All rights reserved.
* Copyright (C) 2011-2013 Red Hat, Inc.
*
* This file is released under the GPL.
*
* dm-switch is a device-mapper target that maps IO to underlying block
* devices efficiently when there are a large number of fixed-sized
* address regions but there is no simple pattern to allow for a compact
* mapping representation such as dm-stripe.
*/
#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#define DM_MSG_PREFIX "switch"
/*
* One region_table_slot_t holds <region_entries_per_slot> region table
* entries each of which is <region_table_entry_bits> in size.
*/
typedef unsigned long region_table_slot_t;
/*
* A device with the offset to its start sector.
*/
struct switch_path {
struct dm_dev *dmdev;
sector_t start;
};
/*
* Context block for a dm switch device.
*/
struct switch_ctx {
struct dm_target *ti;
unsigned nr_paths; /* Number of paths in path_list. */
unsigned region_size; /* Region size in 512-byte sectors */
unsigned long nr_regions; /* Number of regions making up the device */
signed char region_size_bits; /* log2 of region_size or -1 */
unsigned char region_table_entry_bits; /* Number of bits in one region table entry */
unsigned char region_entries_per_slot; /* Number of entries in one region table slot */
signed char region_entries_per_slot_bits; /* log2 of region_entries_per_slot or -1 */
region_table_slot_t *region_table; /* Region table */
/*
* Array of dm devices to switch between.
*/
dm: replace zero-length array with flexible-array The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-05-07 21:51:58 +03:00
struct switch_path path_list[];
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
};
static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_paths,
unsigned region_size)
{
struct switch_ctx *sctx;
dm switch: use struct_size() in kzalloc() One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-08 19:02:33 +03:00
sctx = kzalloc(struct_size(sctx, path_list, nr_paths), GFP_KERNEL);
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
if (!sctx)
return NULL;
sctx->ti = ti;
sctx->region_size = region_size;
ti->private = sctx;
return sctx;
}
static int alloc_region_table(struct dm_target *ti, unsigned nr_paths)
{
struct switch_ctx *sctx = ti->private;
sector_t nr_regions = ti->len;
sector_t nr_slots;
if (!(sctx->region_size & (sctx->region_size - 1)))
sctx->region_size_bits = __ffs(sctx->region_size);
else
sctx->region_size_bits = -1;
sctx->region_table_entry_bits = 1;
while (sctx->region_table_entry_bits < sizeof(region_table_slot_t) * 8 &&
(region_table_slot_t)1 << sctx->region_table_entry_bits < nr_paths)
sctx->region_table_entry_bits++;
sctx->region_entries_per_slot = (sizeof(region_table_slot_t) * 8) / sctx->region_table_entry_bits;
if (!(sctx->region_entries_per_slot & (sctx->region_entries_per_slot - 1)))
sctx->region_entries_per_slot_bits = __ffs(sctx->region_entries_per_slot);
else
sctx->region_entries_per_slot_bits = -1;
if (sector_div(nr_regions, sctx->region_size))
nr_regions++;
dm switch: simplify conditional in alloc_region_table() The variable sctx->nr_regions has type unsigned long and the variable nr_regions has type sector_t. Thus the variables may be different when overflow happens. Changed the conditional to "if (nr_regions >= ULONG_MAX)". Also move the assignment of nr_regions after sector_div() and the sanity check which looks more sane. Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-28 21:54:21 +03:00
if (nr_regions >= ULONG_MAX) {
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
ti->error = "Region table too large";
return -EINVAL;
}
dm switch: simplify conditional in alloc_region_table() The variable sctx->nr_regions has type unsigned long and the variable nr_regions has type sector_t. Thus the variables may be different when overflow happens. Changed the conditional to "if (nr_regions >= ULONG_MAX)". Also move the assignment of nr_regions after sector_div() and the sanity check which looks more sane. Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-28 21:54:21 +03:00
sctx->nr_regions = nr_regions;
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
nr_slots = nr_regions;
if (sector_div(nr_slots, sctx->region_entries_per_slot))
nr_slots++;
if (nr_slots > ULONG_MAX / sizeof(region_table_slot_t)) {
ti->error = "Region table too large";
return -EINVAL;
}
treewide: Use array_size() in vmalloc() The vmalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vmalloc(a * b) with: vmalloc(array_size(a, b)) as well as handling cases of: vmalloc(a * b * c) with: vmalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vmalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(char) * COUNT + COUNT , ...) | vmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vmalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vmalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vmalloc(C1 * C2 * C3, ...) | vmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vmalloc(C1 * C2, ...) | vmalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 00:27:11 +03:00
sctx->region_table = vmalloc(array_size(nr_slots,
sizeof(region_table_slot_t)));
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
if (!sctx->region_table) {
ti->error = "Cannot allocate region table";
return -ENOMEM;
}
return 0;
}
static void switch_get_position(struct switch_ctx *sctx, unsigned long region_nr,
unsigned long *region_index, unsigned *bit)
{
if (sctx->region_entries_per_slot_bits >= 0) {
*region_index = region_nr >> sctx->region_entries_per_slot_bits;
*bit = region_nr & (sctx->region_entries_per_slot - 1);
} else {
*region_index = region_nr / sctx->region_entries_per_slot;
*bit = region_nr % sctx->region_entries_per_slot;
}
*bit *= sctx->region_table_entry_bits;
}
dm switch: factor out switch_region_table_read Move code that reads the table to a switch_region_table_read. It will be needed for the next commit. No functional change. Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 01:49:41 +04:00
static unsigned switch_region_table_read(struct switch_ctx *sctx, unsigned long region_nr)
{
unsigned long region_index;
unsigned bit;
switch_get_position(sctx, region_nr, &region_index, &bit);
locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 00:07:29 +03:00
return (READ_ONCE(sctx->region_table[region_index]) >> bit) &
dm switch: factor out switch_region_table_read Move code that reads the table to a switch_region_table_read. It will be needed for the next commit. No functional change. Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 01:49:41 +04:00
((1 << sctx->region_table_entry_bits) - 1);
}
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
/*
* Find which path to use at given offset.
*/
static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)
{
dm switch: factor out switch_region_table_read Move code that reads the table to a switch_region_table_read. It will be needed for the next commit. No functional change. Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 01:49:41 +04:00
unsigned path_nr;
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
sector_t p;
p = offset;
if (sctx->region_size_bits >= 0)
p >>= sctx->region_size_bits;
else
sector_div(p, sctx->region_size);
dm switch: factor out switch_region_table_read Move code that reads the table to a switch_region_table_read. It will be needed for the next commit. No functional change. Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 01:49:41 +04:00
path_nr = switch_region_table_read(sctx, p);
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
/* This can only happen if the processor uses non-atomic stores. */
if (unlikely(path_nr >= sctx->nr_paths))
path_nr = 0;
return path_nr;
}
static void switch_region_table_write(struct switch_ctx *sctx, unsigned long region_nr,
unsigned value)
{
unsigned long region_index;
unsigned bit;
region_table_slot_t pte;
switch_get_position(sctx, region_nr, &region_index, &bit);
pte = sctx->region_table[region_index];
pte &= ~((((region_table_slot_t)1 << sctx->region_table_entry_bits) - 1) << bit);
pte |= (region_table_slot_t)value << bit;
sctx->region_table[region_index] = pte;
}
/*
* Fill the region table with an initial round robin pattern.
*/
static void initialise_region_table(struct switch_ctx *sctx)
{
unsigned path_nr = 0;
unsigned long region_nr;
for (region_nr = 0; region_nr < sctx->nr_regions; region_nr++) {
switch_region_table_write(sctx, region_nr, path_nr);
if (++path_nr >= sctx->nr_paths)
path_nr = 0;
}
}
static int parse_path(struct dm_arg_set *as, struct dm_target *ti)
{
struct switch_ctx *sctx = ti->private;
unsigned long long start;
int r;
r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
&sctx->path_list[sctx->nr_paths].dmdev);
if (r) {
ti->error = "Device lookup failed";
return r;
}
if (kstrtoull(dm_shift_arg(as), 10, &start) || start != (sector_t)start) {
ti->error = "Invalid device starting offset";
dm_put_device(ti, sctx->path_list[sctx->nr_paths].dmdev);
return -EINVAL;
}
sctx->path_list[sctx->nr_paths].start = start;
sctx->nr_paths++;
return 0;
}
/*
* Destructor: Don't free the dm_target, just the ti->private data (if any).
*/
static void switch_dtr(struct dm_target *ti)
{
struct switch_ctx *sctx = ti->private;
while (sctx->nr_paths--)
dm_put_device(ti, sctx->path_list[sctx->nr_paths].dmdev);
vfree(sctx->region_table);
kfree(sctx);
}
/*
* Constructor arguments:
* <num_paths> <region_size> <num_optional_args> [<optional_args>...]
* [<dev_path> <offset>]+
*
* Optional args are to allow for future extension: currently this
* parameter must be 0.
*/
static int switch_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
dm: constify argument arrays The arrays of 'struct dm_arg' are never modified by the device-mapper core, so constify them so that they are placed in .rodata. (Exception: the args array in dm-raid cannot be constified because it is allocated on the stack and modified.) Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-06-22 21:32:45 +03:00
static const struct dm_arg _args[] = {
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
{1, (KMALLOC_MAX_SIZE - sizeof(struct switch_ctx)) / sizeof(struct switch_path), "Invalid number of paths"},
{1, UINT_MAX, "Invalid region size"},
{0, 0, "Invalid number of optional args"},
};
struct switch_ctx *sctx;
struct dm_arg_set as;
unsigned nr_paths, region_size, nr_optional_args;
int r;
as.argc = argc;
as.argv = argv;
r = dm_read_arg(_args, &as, &nr_paths, &ti->error);
if (r)
return -EINVAL;
r = dm_read_arg(_args + 1, &as, &region_size, &ti->error);
if (r)
return r;
r = dm_read_arg_group(_args + 2, &as, &nr_optional_args, &ti->error);
if (r)
return r;
/* parse optional arguments here, if we add any */
if (as.argc != nr_paths * 2) {
ti->error = "Incorrect number of path arguments";
return -EINVAL;
}
sctx = alloc_switch_ctx(ti, nr_paths, region_size);
if (!sctx) {
ti->error = "Cannot allocate redirection context";
return -ENOMEM;
}
r = dm_set_target_max_io_len(ti, region_size);
if (r)
goto error;
while (as.argc) {
r = parse_path(&as, ti);
if (r)
goto error;
}
r = alloc_region_table(ti, nr_paths);
if (r)
goto error;
initialise_region_table(sctx);
/* For UNMAP, sending the request down any path is sufficient */
ti->num_discard_bios = 1;
return 0;
error:
switch_dtr(ti);
return r;
}
static int switch_map(struct dm_target *ti, struct bio *bio)
{
struct switch_ctx *sctx = ti->private;
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-12 02:44:27 +04:00
sector_t offset = dm_target_offset(ti, bio->bi_iter.bi_sector);
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
unsigned path_nr = switch_get_path_nr(sctx, offset);
block: replace bi_bdev with a gendisk pointer and partitions index This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23 20:10:32 +03:00
bio_set_dev(bio, sctx->path_list[path_nr].dmdev->bdev);
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-12 02:44:27 +04:00
bio->bi_iter.bi_sector = sctx->path_list[path_nr].start + offset;
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
return DM_MAPIO_REMAPPED;
}
/*
* We need to parse hex numbers in the message as quickly as possible.
*
* This table-based hex parser improves performance.
* It improves a time to load 1000000 entries compared to the condition-based
* parser.
* table-based parser condition-based parser
* PA-RISC 0.29s 0.31s
* Opteron 0.0495s 0.0498s
*/
static const unsigned char hex_table[256] = {
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 255, 255, 255, 255, 255, 255,
255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 10, 11, 12, 13, 14, 15, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
};
static __always_inline unsigned long parse_hex(const char **string)
{
unsigned char d;
unsigned long r = 0;
while ((d = hex_table[(unsigned char)**string]) < 16) {
r = (r << 4) | d;
(*string)++;
}
return r;
}
static int process_set_region_mappings(struct switch_ctx *sctx,
dm switch: efficiently support repetitive patterns Add support for quickly loading a repetitive pattern into the dm-switch target. In the "set_regions_mappings" message, the user may now use "Rn,m" as one of the arguments. "n" and "m" are hexadecimal numbers. The "Rn,m" argument repeats the last "n" arguments in the following "m" slots. For example: dmsetup message switch 0 set_region_mappings 1000:1 :2 R2,10 is equivalent to dmsetup message switch 0 set_region_mappings 1000:1 :2 :1 :2 :1 :2 :1 :2 \ :1 :2 :1 :2 :1 :2 :1 :2 :1 :2 Requested-by: Jay Wang <jwang@nimblestorage.com> Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 02:11:25 +04:00
unsigned argc, char **argv)
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
{
unsigned i;
unsigned long region_index = 0;
for (i = 1; i < argc; i++) {
unsigned long path_nr;
const char *string = argv[i];
dm switch: efficiently support repetitive patterns Add support for quickly loading a repetitive pattern into the dm-switch target. In the "set_regions_mappings" message, the user may now use "Rn,m" as one of the arguments. "n" and "m" are hexadecimal numbers. The "Rn,m" argument repeats the last "n" arguments in the following "m" slots. For example: dmsetup message switch 0 set_region_mappings 1000:1 :2 R2,10 is equivalent to dmsetup message switch 0 set_region_mappings 1000:1 :2 :1 :2 :1 :2 :1 :2 \ :1 :2 :1 :2 :1 :2 :1 :2 :1 :2 Requested-by: Jay Wang <jwang@nimblestorage.com> Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 02:11:25 +04:00
if ((*string & 0xdf) == 'R') {
unsigned long cycle_length, num_write;
string++;
if (unlikely(*string == ',')) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
cycle_length = parse_hex(&string);
if (unlikely(*string != ',')) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
string++;
if (unlikely(!*string)) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
num_write = parse_hex(&string);
if (unlikely(*string)) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
if (unlikely(!cycle_length) || unlikely(cycle_length - 1 > region_index)) {
DMWARN("invalid set_region_mappings cycle length: %lu > %lu",
cycle_length - 1, region_index);
return -EINVAL;
}
if (unlikely(region_index + num_write < region_index) ||
unlikely(region_index + num_write >= sctx->nr_regions)) {
DMWARN("invalid set_region_mappings region number: %lu + %lu >= %lu",
region_index, num_write, sctx->nr_regions);
return -EINVAL;
}
while (num_write--) {
region_index++;
path_nr = switch_region_table_read(sctx, region_index - cycle_length);
switch_region_table_write(sctx, region_index, path_nr);
}
continue;
}
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
if (*string == ':')
region_index++;
else {
region_index = parse_hex(&string);
if (unlikely(*string != ':')) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
}
string++;
if (unlikely(!*string)) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
path_nr = parse_hex(&string);
if (unlikely(*string)) {
DMWARN("invalid set_region_mappings argument: '%s'", argv[i]);
return -EINVAL;
}
if (unlikely(region_index >= sctx->nr_regions)) {
DMWARN("invalid set_region_mappings region number: %lu >= %lu", region_index, sctx->nr_regions);
return -EINVAL;
}
if (unlikely(path_nr >= sctx->nr_paths)) {
DMWARN("invalid set_region_mappings device: %lu >= %u", path_nr, sctx->nr_paths);
return -EINVAL;
}
switch_region_table_write(sctx, region_index, path_nr);
}
return 0;
}
/*
* Messages are processed one-at-a-time.
*
* Only set_region_mappings is supported.
*/
dm: allow targets to return output from messages they are sent Could be useful for a target to return stats or other information. If a target does DMEMIT() anything to @result from its .message method then it must return 1 to the caller. Signed-off-By: Mike Snitzer <snitzer@redhat.com>
2018-02-28 23:59:59 +03:00
static int switch_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
{
static DEFINE_MUTEX(message_mutex);
struct switch_ctx *sctx = ti->private;
int r = -EINVAL;
mutex_lock(&message_mutex);
if (!strcasecmp(argv[0], "set_region_mappings"))
r = process_set_region_mappings(sctx, argc, argv);
else
DMWARN("Unrecognised message received.");
mutex_unlock(&message_mutex);
return r;
}
static void switch_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct switch_ctx *sctx = ti->private;
unsigned sz = 0;
int path_nr;
switch (type) {
case STATUSTYPE_INFO:
result[0] = '\0';
break;
case STATUSTYPE_TABLE:
DMEMIT("%u %u 0", sctx->nr_paths, sctx->region_size);
for (path_nr = 0; path_nr < sctx->nr_paths; path_nr++)
DMEMIT(" %s %llu", sctx->path_list[path_nr].dmdev->name,
(unsigned long long)sctx->path_list[path_nr].start);
break;
}
}
/*
* Switch ioctl:
*
* Passthrough all ioctls to the path for sector 0
*/
dm: remove fmode_t argument from .prepare_ioctl hook Use the fmode_t that is passed to dm_blk_ioctl() rather than inconsistently (varies across targets) drop it on the floor by overriding it with the fmode_t stored in 'struct dm_dev'. All the persistent reservation functions weren't using the fmode_t they got back from .prepare_ioctl so remove them. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-03 23:54:10 +03:00
static int switch_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
{
struct switch_ctx *sctx = ti->private;
unsigned path_nr;
path_nr = switch_get_path_nr(sctx, 0);
dm: refactor ioctl handling This moves the call to blkdev_ioctl and the argument checking to DM core code, and only leaves a callout to find the block device to operate on in the targets. This simplifies the code and allows us to pass through ioctl-like command using other methods in the next patch. Also split out a helper around calling the prepare_ioctl method that will be reused for persistent reservation handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-15 15:10:50 +03:00
*bdev = sctx->path_list[path_nr].dmdev->bdev;
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
/*
* Only pass ioctls through if the device sizes match exactly.
*/
dm: refactor ioctl handling This moves the call to blkdev_ioctl and the argument checking to DM core code, and only leaves a callout to find the block device to operate on in the targets. This simplifies the code and allows us to pass through ioctl-like command using other methods in the next patch. Also split out a helper around calling the prepare_ioctl method that will be reused for persistent reservation handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-15 15:10:50 +03:00
if (ti->len + sctx->path_list[path_nr].start !=
i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
return 1;
return 0;
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
}
static int switch_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct switch_ctx *sctx = ti->private;
int path_nr;
int r;
for (path_nr = 0; path_nr < sctx->nr_paths; path_nr++) {
r = fn(ti, sctx->path_list[path_nr].dmdev,
sctx->path_list[path_nr].start, ti->len, data);
if (r)
return r;
}
return 0;
}
static struct target_type switch_target = {
.name = "switch",
dm switch: efficiently support repetitive patterns Add support for quickly loading a repetitive pattern into the dm-switch target. In the "set_regions_mappings" message, the user may now use "Rn,m" as one of the arguments. "n" and "m" are hexadecimal numbers. The "Rn,m" argument repeats the last "n" arguments in the following "m" slots. For example: dmsetup message switch 0 set_region_mappings 1000:1 :2 R2,10 is equivalent to dmsetup message switch 0 set_region_mappings 1000:1 :2 :1 :2 :1 :2 :1 :2 \ :1 :2 :1 :2 :1 :2 :1 :2 :1 :2 Requested-by: Jay Wang <jwang@nimblestorage.com> Tested-by: Jay Wang <jwang@nimblestorage.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-07-29 02:11:25 +04:00
.version = {1, 1, 0},
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
.module = THIS_MODULE,
.ctr = switch_ctr,
.dtr = switch_dtr,
.map = switch_map,
.message = switch_message,
.status = switch_status,
dm: refactor ioctl handling This moves the call to blkdev_ioctl and the argument checking to DM core code, and only leaves a callout to find the block device to operate on in the targets. This simplifies the code and allows us to pass through ioctl-like command using other methods in the next patch. Also split out a helper around calling the prepare_ioctl method that will be reused for persistent reservation handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-15 15:10:50 +03:00
.prepare_ioctl = switch_prepare_ioctl,
dm: add switch target dm-switch is a new target that maps IO to underlying block devices efficiently when there is a large number of fixed-sized address regions but there is no simple pattern to allow for a compact mapping representation such as dm-stripe. Though we have developed this target for a specific storage device, Dell EqualLogic, we have made an effort to keep it as general purpose as possible in the hope that others may benefit. Originally developed by Jim Ramsay. Simplified by Mikulas Patocka. Signed-off-by: Jim Ramsay <jim_ramsay@dell.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-07-11 02:41:19 +04:00
.iterate_devices = switch_iterate_devices,
};
static int __init dm_switch_init(void)
{
int r;
r = dm_register_target(&switch_target);
if (r < 0)
DMERR("dm_register_target() failed %d", r);
return r;
}
static void __exit dm_switch_exit(void)
{
dm_unregister_target(&switch_target);
}
module_init(dm_switch_init);
module_exit(dm_switch_exit);
MODULE_DESCRIPTION(DM_NAME " dynamic path switching target");
MODULE_AUTHOR("Kevin D. O'Kelley <Kevin_OKelley@dell.com>");
MODULE_AUTHOR("Narendran Ganapathy <Narendran_Ganapathy@dell.com>");
MODULE_AUTHOR("Jim Ramsay <Jim_Ramsay@dell.com>");
MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
MODULE_LICENSE("GPL");