When a bio completion calls back into the transport for a back-end io device, the request completion path can free the transport io job structure allowing it to be reused for other operations. The transport has a defer_rcv queue which holds temporary cmd rcv ops while waitng for io job structures. when the job frees, if there's a cmd waiting, it is picked up and submitted for processing, which can call back out to the bio path if it's a read. Unfortunately, what is unknown is the context of the original bio done call, and it may be in a state (softirq) that is not compatible with submitting the new bio in the same calling sequence. This is especially true when using scsi back-end devices as scsi is in softirq when it makes the done call. Correct by scheduling the io to be started via workq rather than calling the start new io path inline to the original bio done path. Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.