Currently the code doesn't recognize asynchronous calls passed
by io_submit() and processes all calls synchronously. This is not
what kernel AIO expects. This patch introduces a new async context
that keeps track of all issued i/o requests and moves a response
collecting procedure to a separate thread. This allows to return
to a caller immediately for async calls and call iocb->ki_complete()
once all requests are completed. For sync calls the current thread
simply waits until all requests are completed.
Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
---
fs/cifs/cifsglob.h | 16 +++++++
fs/cifs/cifsproto.h | 3 ++
fs/cifs/misc.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 139 insertions(+)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 37f5a41..bb41226 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1115,6 +1115,22 @@ struct cifs_io_parms {
struct cifs_tcon *tcon;
};
+struct cifs_aio_ctx {
+ struct kref refcount;
+ struct list_head list;
+ struct mutex aio_mutex;
+ struct completion done;
+ struct iov_iter iter;
+ struct kiocb *iocb;
+ struct cifsFileInfo *cfile;
+ struct bio_vec *bv;
+ unsigned int npages;
+ ssize_t rc;
+ unsigned int len;
+ unsigned int total_len;
+ bool should_dirty;
+};
+
struct cifs_readdata;
/* asynchronous read support */
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 97e5d23..e49958c 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -535,4 +535,7 @@ int __cifs_calc_signature(struct smb_rqst *rqst,
struct shash_desc *shash);
enum securityEnum cifs_select_sectype(struct TCP_Server_Info *,
enum securityEnum);
+struct cifs_aio_ctx *cifs_aio_ctx_alloc(void);
+void cifs_aio_ctx_release(struct kref *refcount);
+int setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw);
#endif /* _CIFSPROTO_H */
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index d3fb115..c214d77 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/mempool.h>
+#include <linux/vmalloc.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
@@ -745,3 +746,122 @@ parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
}
return rc;
}
+
+struct cifs_aio_ctx *
+cifs_aio_ctx_alloc(void)
+{
+ struct cifs_aio_ctx *ctx;
+
+ ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
+ if (!ctx)
+ return NULL;
+
+ INIT_LIST_HEAD(&ctx->list);
+ mutex_init(&ctx->aio_mutex);
+ init_completion(&ctx->done);
+ kref_init(&ctx->refcount);
+ return ctx;
+}
+
+void
+cifs_aio_ctx_release(struct kref *refcount)
+{
+ struct cifs_aio_ctx *ctx = container_of(refcount,
+ struct cifs_aio_ctx, refcount);
+
+ cifsFileInfo_put(ctx->cfile);
+ kvfree(ctx->bv);
+ kfree(ctx);
+}
+
+#define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
+
+int
+setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
+{
+ ssize_t rc;
+ unsigned int cur_npages;
+ unsigned int npages = 0;
+ unsigned int i;
+ size_t len;
+ size_t count = iov_iter_count(iter);
+ unsigned int saved_len;
+ size_t start;
+ unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
+ struct page **pages = NULL;
+ struct bio_vec *bv = NULL;
+
+ if (iter->type & ITER_KVEC) {
+ memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
+ ctx->len = count;
+ iov_iter_advance(iter, count);
+ return 0;
+ }
+
+ if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
+ bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
+ GFP_KERNEL);
+
+ if (!bv) {
+ bv = vmalloc(max_pages * sizeof(struct bio_vec));
+ if (!bv)
+ return -ENOMEM;
+ }
+
+ if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
+ pages = kmalloc_array(max_pages, sizeof(struct page *),
+ GFP_KERNEL);
+
+ if (!pages) {
+ pages = vmalloc(max_pages * sizeof(struct page *));
+ if (!bv) {
+ kvfree(bv);
+ return -ENOMEM;
+ }
+ }
+
+ saved_len = count;
+
+ while (count && npages < max_pages) {
+ rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
+ if (rc < 0) {
+ cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
+ break;
+ }
+
+ if (rc > count) {
+ cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
+ count);
+ break;
+ }
+
+ iov_iter_advance(iter, rc);
+ count -= rc;
+ rc += start;
+ cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
+
+ if (npages + cur_npages > max_pages) {
+ cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
+ npages + cur_npages, max_pages);
+ break;
+ }
+
+ for (i = 0; i < cur_npages; i++) {
+ len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
+ bv[npages + i].bv_page = pages[i];
+ bv[npages + i].bv_offset = start;
+ bv[npages + i].bv_len = len - start;
+ rc -= len;
+ start = 0;
+ }
+
+ npages += cur_npages;
+ }
+
+ kvfree(pages);
+ ctx->bv = bv;
+ ctx->len = saved_len - count;
+ ctx->npages = npages;
+ iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
+ return 0;
+}
--
2.7.4
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