scsi: cxlflash: Support adapter file descriptors for OCXL
Allocate a file descriptor for an adapter context when requested. In order to allocate inodes for the file descriptors, a pseudo filesystem is created and used. Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com> Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Uma Krishnan
Martin K. Petersen
Родитель
429ebfa69b
Коммит
926a62f9bd
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@ -12,13 +12,144 @@
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/file.h>
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#include <linux/idr.h>
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#include <linux/module.h>
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#include <linux/mount.h>
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#include <misc/ocxl.h>
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#include "backend.h"
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#include "ocxl_hw.h"
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/*
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* Pseudo-filesystem to allocate inodes.
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*/
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#define OCXLFLASH_FS_MAGIC 0x1697698f
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static int ocxlflash_fs_cnt;
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static struct vfsmount *ocxlflash_vfs_mount;
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static const struct dentry_operations ocxlflash_fs_dops = {
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.d_dname = simple_dname,
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};
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/*
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* ocxlflash_fs_mount() - mount the pseudo-filesystem
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* @fs_type: File system type.
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* @flags: Flags for the filesystem.
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* @dev_name: Device name associated with the filesystem.
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* @data: Data pointer.
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*
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* Return: pointer to the directory entry structure
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*/
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static struct dentry *ocxlflash_fs_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name,
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void *data)
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{
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return mount_pseudo(fs_type, "ocxlflash:", NULL, &ocxlflash_fs_dops,
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OCXLFLASH_FS_MAGIC);
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}
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static struct file_system_type ocxlflash_fs_type = {
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.name = "ocxlflash",
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.owner = THIS_MODULE,
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.mount = ocxlflash_fs_mount,
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.kill_sb = kill_anon_super,
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};
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/*
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* ocxlflash_release_mapping() - release the memory mapping
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* @ctx: Context whose mapping is to be released.
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*/
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static void ocxlflash_release_mapping(struct ocxlflash_context *ctx)
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{
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if (ctx->mapping)
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simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt);
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ctx->mapping = NULL;
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}
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/*
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* ocxlflash_getfile() - allocate pseudo filesystem, inode, and the file
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* @dev: Generic device of the host.
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* @name: Name of the pseudo filesystem.
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* @fops: File operations.
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* @priv: Private data.
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* @flags: Flags for the file.
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*
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* Return: pointer to the file on success, ERR_PTR on failure
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*/
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static struct file *ocxlflash_getfile(struct device *dev, const char *name,
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const struct file_operations *fops,
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void *priv, int flags)
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{
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struct qstr this;
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struct path path;
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struct file *file;
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struct inode *inode = NULL;
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int rc;
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if (fops->owner && !try_module_get(fops->owner)) {
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dev_err(dev, "%s: Owner does not exist\n", __func__);
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rc = -ENOENT;
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goto err1;
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}
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rc = simple_pin_fs(&ocxlflash_fs_type, &ocxlflash_vfs_mount,
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&ocxlflash_fs_cnt);
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if (unlikely(rc < 0)) {
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dev_err(dev, "%s: Cannot mount ocxlflash pseudofs rc=%d\n",
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__func__, rc);
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goto err2;
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}
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inode = alloc_anon_inode(ocxlflash_vfs_mount->mnt_sb);
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if (IS_ERR(inode)) {
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rc = PTR_ERR(inode);
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dev_err(dev, "%s: alloc_anon_inode failed rc=%d\n",
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__func__, rc);
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goto err3;
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}
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this.name = name;
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this.len = strlen(name);
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this.hash = 0;
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path.dentry = d_alloc_pseudo(ocxlflash_vfs_mount->mnt_sb, &this);
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if (!path.dentry) {
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dev_err(dev, "%s: d_alloc_pseudo failed\n", __func__);
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rc = -ENOMEM;
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goto err4;
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}
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path.mnt = mntget(ocxlflash_vfs_mount);
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d_instantiate(path.dentry, inode);
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file = alloc_file(&path, OPEN_FMODE(flags), fops);
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if (IS_ERR(file)) {
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rc = PTR_ERR(file);
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dev_err(dev, "%s: alloc_file failed rc=%d\n",
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__func__, rc);
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goto err5;
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}
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file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);
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file->private_data = priv;
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out:
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return file;
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err5:
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path_put(&path);
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err4:
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iput(inode);
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err3:
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simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt);
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err2:
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module_put(fops->owner);
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err1:
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file = ERR_PTR(rc);
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goto out;
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}
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/**
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* ocxlflash_set_master() - sets the context as master
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* @ctx_cookie: Adapter context to set as master.
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@ -75,6 +206,7 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie)
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ctx->pe = rc;
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ctx->master = false;
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ctx->mapping = NULL;
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ctx->hw_afu = afu;
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out:
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return ctx;
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@ -100,6 +232,7 @@ static int ocxlflash_release_context(void *ctx_cookie)
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goto out;
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idr_remove(&ctx->hw_afu->idr, ctx->pe);
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ocxlflash_release_mapping(ctx);
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kfree(ctx);
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out:
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return rc;
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@ -270,6 +403,72 @@ err1:
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goto out;
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}
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static const struct file_operations ocxl_afu_fops = {
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.owner = THIS_MODULE,
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};
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/**
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* ocxlflash_get_fd() - get file descriptor for an adapter context
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* @ctx_cookie: Adapter context.
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* @fops: File operations to be associated.
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* @fd: File descriptor to be returned back.
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*
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* Return: pointer to the file on success, ERR_PTR on failure
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*/
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static struct file *ocxlflash_get_fd(void *ctx_cookie,
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struct file_operations *fops, int *fd)
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{
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struct ocxlflash_context *ctx = ctx_cookie;
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struct device *dev = ctx->hw_afu->dev;
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struct file *file;
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int flags, fdtmp;
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int rc = 0;
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char *name = NULL;
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/* Only allow one fd per context */
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if (ctx->mapping) {
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dev_err(dev, "%s: Context is already mapped to an fd\n",
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__func__);
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rc = -EEXIST;
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goto err1;
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}
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flags = O_RDWR | O_CLOEXEC;
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/* This code is similar to anon_inode_getfd() */
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rc = get_unused_fd_flags(flags);
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if (unlikely(rc < 0)) {
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dev_err(dev, "%s: get_unused_fd_flags failed rc=%d\n",
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__func__, rc);
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goto err1;
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}
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fdtmp = rc;
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/* Use default ops if there is no fops */
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if (!fops)
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fops = (struct file_operations *)&ocxl_afu_fops;
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name = kasprintf(GFP_KERNEL, "ocxlflash:%d", ctx->pe);
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file = ocxlflash_getfile(dev, name, fops, ctx, flags);
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kfree(name);
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if (IS_ERR(file)) {
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rc = PTR_ERR(file);
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dev_err(dev, "%s: ocxlflash_getfile failed rc=%d\n",
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__func__, rc);
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goto err2;
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}
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ctx->mapping = file->f_mapping;
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*fd = fdtmp;
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out:
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return file;
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err2:
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put_unused_fd(fdtmp);
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err1:
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file = ERR_PTR(rc);
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goto out;
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}
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/* Backend ops to ocxlflash services */
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const struct cxlflash_backend_ops cxlflash_ocxl_ops = {
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.module = THIS_MODULE,
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@ -279,4 +478,5 @@ const struct cxlflash_backend_ops cxlflash_ocxl_ops = {
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.release_context = ocxlflash_release_context,
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.create_afu = ocxlflash_create_afu,
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.destroy_afu = ocxlflash_destroy_afu,
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.get_fd = ocxlflash_get_fd,
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};
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@ -33,6 +33,7 @@ struct ocxl_hw_afu {
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struct ocxlflash_context {
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struct ocxl_hw_afu *hw_afu; /* HW AFU back pointer */
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struct address_space *mapping; /* Mapping for pseudo filesystem */
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bool master; /* Whether this is a master context */
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int pe; /* Process element */
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};
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