From 926a62f9bd53f5ad411e831eeb259a9564fb1532 Mon Sep 17 00:00:00 2001 From: Uma Krishnan Date: Mon, 26 Mar 2018 11:32:09 -0500 Subject: [PATCH] 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 Acked-by: Matthew R. Ochs Signed-off-by: Martin K. Petersen --- drivers/scsi/cxlflash/ocxl_hw.c | 200 ++++++++++++++++++++++++++++++++++++++++ drivers/scsi/cxlflash/ocxl_hw.h | 1 + 2 files changed, 201 insertions(+) diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c index e8864a1..49af059 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.c +++ b/drivers/scsi/cxlflash/ocxl_hw.c @@ -12,13 +12,144 @@ * 2 of the License, or (at your option) any later version. */ +#include #include +#include +#include #include #include "backend.h" #include "ocxl_hw.h" +/* + * Pseudo-filesystem to allocate inodes. + */ + +#define OCXLFLASH_FS_MAGIC 0x1697698f + +static int ocxlflash_fs_cnt; +static struct vfsmount *ocxlflash_vfs_mount; + +static const struct dentry_operations ocxlflash_fs_dops = { + .d_dname = simple_dname, +}; + +/* + * ocxlflash_fs_mount() - mount the pseudo-filesystem + * @fs_type: File system type. + * @flags: Flags for the filesystem. + * @dev_name: Device name associated with the filesystem. + * @data: Data pointer. + * + * Return: pointer to the directory entry structure + */ +static struct dentry *ocxlflash_fs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, + void *data) +{ + return mount_pseudo(fs_type, "ocxlflash:", NULL, &ocxlflash_fs_dops, + OCXLFLASH_FS_MAGIC); +} + +static struct file_system_type ocxlflash_fs_type = { + .name = "ocxlflash", + .owner = THIS_MODULE, + .mount = ocxlflash_fs_mount, + .kill_sb = kill_anon_super, +}; + +/* + * ocxlflash_release_mapping() - release the memory mapping + * @ctx: Context whose mapping is to be released. + */ +static void ocxlflash_release_mapping(struct ocxlflash_context *ctx) +{ + if (ctx->mapping) + simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt); + ctx->mapping = NULL; +} + +/* + * ocxlflash_getfile() - allocate pseudo filesystem, inode, and the file + * @dev: Generic device of the host. + * @name: Name of the pseudo filesystem. + * @fops: File operations. + * @priv: Private data. + * @flags: Flags for the file. + * + * Return: pointer to the file on success, ERR_PTR on failure + */ +static struct file *ocxlflash_getfile(struct device *dev, const char *name, + const struct file_operations *fops, + void *priv, int flags) +{ + struct qstr this; + struct path path; + struct file *file; + struct inode *inode = NULL; + int rc; + + if (fops->owner && !try_module_get(fops->owner)) { + dev_err(dev, "%s: Owner does not exist\n", __func__); + rc = -ENOENT; + goto err1; + } + + rc = simple_pin_fs(&ocxlflash_fs_type, &ocxlflash_vfs_mount, + &ocxlflash_fs_cnt); + if (unlikely(rc < 0)) { + dev_err(dev, "%s: Cannot mount ocxlflash pseudofs rc=%d\n", + __func__, rc); + goto err2; + } + + inode = alloc_anon_inode(ocxlflash_vfs_mount->mnt_sb); + if (IS_ERR(inode)) { + rc = PTR_ERR(inode); + dev_err(dev, "%s: alloc_anon_inode failed rc=%d\n", + __func__, rc); + goto err3; + } + + this.name = name; + this.len = strlen(name); + this.hash = 0; + path.dentry = d_alloc_pseudo(ocxlflash_vfs_mount->mnt_sb, &this); + if (!path.dentry) { + dev_err(dev, "%s: d_alloc_pseudo failed\n", __func__); + rc = -ENOMEM; + goto err4; + } + + path.mnt = mntget(ocxlflash_vfs_mount); + d_instantiate(path.dentry, inode); + + file = alloc_file(&path, OPEN_FMODE(flags), fops); + if (IS_ERR(file)) { + rc = PTR_ERR(file); + dev_err(dev, "%s: alloc_file failed rc=%d\n", + __func__, rc); + goto err5; + } + + file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); + file->private_data = priv; +out: + return file; +err5: + path_put(&path); +err4: + iput(inode); +err3: + simple_release_fs(&ocxlflash_vfs_mount, &ocxlflash_fs_cnt); +err2: + module_put(fops->owner); +err1: + file = ERR_PTR(rc); + goto out; +} + /** * ocxlflash_set_master() - sets the context as master * @ctx_cookie: Adapter context to set as master. @@ -75,6 +206,7 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie) ctx->pe = rc; ctx->master = false; + ctx->mapping = NULL; ctx->hw_afu = afu; out: return ctx; @@ -100,6 +232,7 @@ static int ocxlflash_release_context(void *ctx_cookie) goto out; idr_remove(&ctx->hw_afu->idr, ctx->pe); + ocxlflash_release_mapping(ctx); kfree(ctx); out: return rc; @@ -270,6 +403,72 @@ err1: goto out; } +static const struct file_operations ocxl_afu_fops = { + .owner = THIS_MODULE, +}; + +/** + * ocxlflash_get_fd() - get file descriptor for an adapter context + * @ctx_cookie: Adapter context. + * @fops: File operations to be associated. + * @fd: File descriptor to be returned back. + * + * Return: pointer to the file on success, ERR_PTR on failure + */ +static struct file *ocxlflash_get_fd(void *ctx_cookie, + struct file_operations *fops, int *fd) +{ + struct ocxlflash_context *ctx = ctx_cookie; + struct device *dev = ctx->hw_afu->dev; + struct file *file; + int flags, fdtmp; + int rc = 0; + char *name = NULL; + + /* Only allow one fd per context */ + if (ctx->mapping) { + dev_err(dev, "%s: Context is already mapped to an fd\n", + __func__); + rc = -EEXIST; + goto err1; + } + + flags = O_RDWR | O_CLOEXEC; + + /* This code is similar to anon_inode_getfd() */ + rc = get_unused_fd_flags(flags); + if (unlikely(rc < 0)) { + dev_err(dev, "%s: get_unused_fd_flags failed rc=%d\n", + __func__, rc); + goto err1; + } + fdtmp = rc; + + /* Use default ops if there is no fops */ + if (!fops) + fops = (struct file_operations *)&ocxl_afu_fops; + + name = kasprintf(GFP_KERNEL, "ocxlflash:%d", ctx->pe); + file = ocxlflash_getfile(dev, name, fops, ctx, flags); + kfree(name); + if (IS_ERR(file)) { + rc = PTR_ERR(file); + dev_err(dev, "%s: ocxlflash_getfile failed rc=%d\n", + __func__, rc); + goto err2; + } + + ctx->mapping = file->f_mapping; + *fd = fdtmp; +out: + return file; +err2: + put_unused_fd(fdtmp); +err1: + file = ERR_PTR(rc); + goto out; +} + /* Backend ops to ocxlflash services */ const struct cxlflash_backend_ops cxlflash_ocxl_ops = { .module = THIS_MODULE, @@ -279,4 +478,5 @@ const struct cxlflash_backend_ops cxlflash_ocxl_ops = { .release_context = ocxlflash_release_context, .create_afu = ocxlflash_create_afu, .destroy_afu = ocxlflash_destroy_afu, + .get_fd = ocxlflash_get_fd, }; diff --git a/drivers/scsi/cxlflash/ocxl_hw.h b/drivers/scsi/cxlflash/ocxl_hw.h index a5337b6..55db005 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.h +++ b/drivers/scsi/cxlflash/ocxl_hw.h @@ -33,6 +33,7 @@ struct ocxl_hw_afu { struct ocxlflash_context { struct ocxl_hw_afu *hw_afu; /* HW AFU back pointer */ + struct address_space *mapping; /* Mapping for pseudo filesystem */ bool master; /* Whether this is a master context */ int pe; /* Process element */ }; -- 2.7.4