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-rw-r--r--fs/cifs/cifsproto.h2
-rw-r--r--fs/cifs/file.c294
2 files changed, 236 insertions, 60 deletions
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 63e91c79564d..eeb789d8e855 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -465,6 +465,8 @@ extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
/* asynchronous read support */
struct cifs_readdata {
struct kref refcount;
+ struct list_head list;
+ struct completion done;
struct cifsFileInfo *cfile;
struct address_space *mapping;
__u64 offset;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index d2a4259408e6..4b5fe398cbf6 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2348,6 +2348,8 @@ cifs_readdata_alloc(unsigned int nr_vecs, work_func_t complete)
sizeof(struct kvec) * nr_vecs, GFP_KERNEL);
if (rdata != NULL) {
kref_init(&rdata->refcount);
+ INIT_LIST_HEAD(&rdata->list);
+ init_completion(&rdata->done);
INIT_WORK(&rdata->work, complete);
INIT_LIST_HEAD(&rdata->pages);
}
@@ -2367,6 +2369,45 @@ cifs_readdata_release(struct kref *refcount)
}
static int
+cifs_read_allocate_pages(struct list_head *list, unsigned int npages)
+{
+ int rc = 0;
+ struct page *page, *tpage;
+ unsigned int i;
+
+ for (i = 0; i < npages; i++) {
+ page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+ if (!page) {
+ rc = -ENOMEM;
+ break;
+ }
+ list_add(&page->lru, list);
+ }
+
+ if (rc) {
+ list_for_each_entry_safe(page, tpage, list, lru) {
+ list_del(&page->lru);
+ put_page(page);
+ }
+ }
+ return rc;
+}
+
+static void
+cifs_uncached_readdata_release(struct kref *refcount)
+{
+ struct page *page, *tpage;
+ struct cifs_readdata *rdata = container_of(refcount,
+ struct cifs_readdata, refcount);
+
+ list_for_each_entry_safe(page, tpage, &rdata->pages, lru) {
+ list_del(&page->lru);
+ put_page(page);
+ }
+ cifs_readdata_release(refcount);
+}
+
+static int
cifs_retry_async_readv(struct cifs_readdata *rdata)
{
int rc;
@@ -2383,24 +2424,139 @@ cifs_retry_async_readv(struct cifs_readdata *rdata)
return rc;
}
+/**
+ * cifs_readdata_to_iov - copy data from pages in response to an iovec
+ * @rdata: the readdata response with list of pages holding data
+ * @iov: vector in which we should copy the data
+ * @nr_segs: number of segments in vector
+ * @offset: offset into file of the first iovec
+ * @copied: used to return the amount of data copied to the iov
+ *
+ * This function copies data from a list of pages in a readdata response into
+ * an array of iovecs. It will first calculate where the data should go
+ * based on the info in the readdata and then copy the data into that spot.
+ */
+static ssize_t
+cifs_readdata_to_iov(struct cifs_readdata *rdata, const struct iovec *iov,
+ unsigned long nr_segs, loff_t offset, ssize_t *copied)
+{
+ int rc = 0;
+ struct iov_iter ii;
+ size_t pos = rdata->offset - offset;
+ struct page *page, *tpage;
+ ssize_t remaining = rdata->bytes;
+ unsigned char *pdata;
+
+ /* set up iov_iter and advance to the correct offset */
+ iov_iter_init(&ii, iov, nr_segs, iov_length(iov, nr_segs), 0);
+ iov_iter_advance(&ii, pos);
+
+ *copied = 0;
+ list_for_each_entry_safe(page, tpage, &rdata->pages, lru) {
+ ssize_t copy;
+
+ /* copy a whole page or whatever's left */
+ copy = min_t(ssize_t, remaining, PAGE_SIZE);
+
+ /* ...but limit it to whatever space is left in the iov */
+ copy = min_t(ssize_t, copy, iov_iter_count(&ii));
+
+ /* go while there's data to be copied and no errors */
+ if (copy && !rc) {
+ pdata = kmap(page);
+ rc = memcpy_toiovecend(ii.iov, pdata, ii.iov_offset,
+ (int)copy);
+ kunmap(page);
+ if (!rc) {
+ *copied += copy;
+ remaining -= copy;
+ iov_iter_advance(&ii, copy);
+ }
+ }
+
+ list_del(&page->lru);
+ put_page(page);
+ }
+
+ return rc;
+}
+
+static void
+cifs_uncached_readv_complete(struct work_struct *work)
+{
+ struct cifs_readdata *rdata = container_of(work,
+ struct cifs_readdata, work);
+
+ /* if the result is non-zero then the pages weren't kmapped */
+ if (rdata->result == 0) {
+ struct page *page;
+
+ list_for_each_entry(page, &rdata->pages, lru)
+ kunmap(page);
+ }
+
+ complete(&rdata->done);
+ kref_put(&rdata->refcount, cifs_uncached_readdata_release);
+}
+
+static int
+cifs_uncached_read_marshal_iov(struct cifs_readdata *rdata,
+ unsigned int remaining)
+{
+ int len = 0;
+ struct page *page, *tpage;
+
+ rdata->nr_iov = 1;
+ list_for_each_entry_safe(page, tpage, &rdata->pages, lru) {
+ if (remaining >= PAGE_SIZE) {
+ /* enough data to fill the page */
+ rdata->iov[rdata->nr_iov].iov_base = kmap(page);
+ rdata->iov[rdata->nr_iov].iov_len = PAGE_SIZE;
+ cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
+ rdata->nr_iov, page->index,
+ rdata->iov[rdata->nr_iov].iov_base,
+ rdata->iov[rdata->nr_iov].iov_len);
+ ++rdata->nr_iov;
+ len += PAGE_SIZE;
+ remaining -= PAGE_SIZE;
+ } else if (remaining > 0) {
+ /* enough for partial page, fill and zero the rest */
+ rdata->iov[rdata->nr_iov].iov_base = kmap(page);
+ rdata->iov[rdata->nr_iov].iov_len = remaining;
+ cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu",
+ rdata->nr_iov, page->index,
+ rdata->iov[rdata->nr_iov].iov_base,
+ rdata->iov[rdata->nr_iov].iov_len);
+ memset(rdata->iov[rdata->nr_iov].iov_base + remaining,
+ '\0', PAGE_SIZE - remaining);
+ ++rdata->nr_iov;
+ len += remaining;
+ remaining = 0;
+ } else {
+ /* no need to hold page hostage */
+ list_del(&page->lru);
+ put_page(page);
+ }
+ }
+
+ return len;
+}
+
static ssize_t
cifs_iovec_read(struct file *file, const struct iovec *iov,
unsigned long nr_segs, loff_t *poffset)
{
- int rc;
- int xid;
- ssize_t total_read;
- unsigned int bytes_read = 0;
+ ssize_t rc;
size_t len, cur_len;
- int iov_offset = 0;
+ ssize_t total_read = 0;
+ loff_t offset = *poffset;
+ unsigned int npages;
struct cifs_sb_info *cifs_sb;
- struct cifs_tcon *pTcon;
+ struct cifs_tcon *tcon;
struct cifsFileInfo *open_file;
- struct smb_com_read_rsp *pSMBr;
- struct cifs_io_parms io_parms;
- char *read_data;
- unsigned int rsize;
- __u32 pid;
+ struct cifs_readdata *rdata, *tmp;
+ struct list_head rdata_list;
+ pid_t pid;
if (!nr_segs)
return 0;
@@ -2409,14 +2565,10 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
if (!len)
return 0;
- xid = GetXid();
+ INIT_LIST_HEAD(&rdata_list);
cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-
- /* FIXME: set up handlers for larger reads and/or convert to async */
- rsize = min_t(unsigned int, cifs_sb->rsize, CIFSMaxBufSize);
-
open_file = file->private_data;
- pTcon = tlink_tcon(open_file->tlink);
+ tcon = tlink_tcon(open_file->tlink);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
@@ -2426,56 +2578,78 @@ cifs_iovec_read(struct file *file, const struct iovec *iov,
if ((file->f_flags & O_ACCMODE) == O_WRONLY)
cFYI(1, "attempting read on write only file instance");
- for (total_read = 0; total_read < len; total_read += bytes_read) {
- cur_len = min_t(const size_t, len - total_read, rsize);
- rc = -EAGAIN;
- read_data = NULL;
+ do {
+ cur_len = min_t(const size_t, len - total_read, cifs_sb->rsize);
+ npages = DIV_ROUND_UP(cur_len, PAGE_SIZE);
- while (rc == -EAGAIN) {
- int buf_type = CIFS_NO_BUFFER;
- if (open_file->invalidHandle) {
- rc = cifs_reopen_file(open_file, true);
- if (rc != 0)
- break;
- }
- io_parms.netfid = open_file->netfid;
- io_parms.pid = pid;
- io_parms.tcon = pTcon;
- io_parms.offset = *poffset;
- io_parms.length = cur_len;
- rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
- &read_data, &buf_type);
- pSMBr = (struct smb_com_read_rsp *)read_data;
- if (read_data) {
- char *data_offset = read_data + 4 +
- le16_to_cpu(pSMBr->DataOffset);
- if (memcpy_toiovecend(iov, data_offset,
- iov_offset, bytes_read))
- rc = -EFAULT;
- if (buf_type == CIFS_SMALL_BUFFER)
- cifs_small_buf_release(read_data);
- else if (buf_type == CIFS_LARGE_BUFFER)
- cifs_buf_release(read_data);
- read_data = NULL;
- iov_offset += bytes_read;
- }
+ /* allocate a readdata struct */
+ rdata = cifs_readdata_alloc(npages,
+ cifs_uncached_readv_complete);
+ if (!rdata) {
+ rc = -ENOMEM;
+ goto error;
}
- if (rc || (bytes_read == 0)) {
- if (total_read) {
- break;
- } else {
- FreeXid(xid);
- return rc;
+ rc = cifs_read_allocate_pages(&rdata->pages, npages);
+ if (rc)
+ goto error;
+
+ rdata->cfile = cifsFileInfo_get(open_file);
+ rdata->offset = offset;
+ rdata->bytes = cur_len;
+ rdata->pid = pid;
+ rdata->marshal_iov = cifs_uncached_read_marshal_iov;
+
+ rc = cifs_retry_async_readv(rdata);
+error:
+ if (rc) {
+ kref_put(&rdata->refcount,
+ cifs_uncached_readdata_release);
+ break;
+ }
+
+ list_add_tail(&rdata->list, &rdata_list);
+ offset += cur_len;
+ len -= cur_len;
+ } while (len > 0);
+
+ /* if at least one read request send succeeded, then reset rc */
+ if (!list_empty(&rdata_list))
+ rc = 0;
+
+ /* the loop below should proceed in the order of increasing offsets */
+restart_loop:
+ list_for_each_entry_safe(rdata, tmp, &rdata_list, list) {
+ if (!rc) {
+ ssize_t copied;
+
+ /* FIXME: freezable sleep too? */
+ rc = wait_for_completion_killable(&rdata->done);
+ if (rc)
+ rc = -EINTR;
+ else if (rdata->result)
+ rc = rdata->result;
+ else {
+ rc = cifs_readdata_to_iov(rdata, iov,
+ nr_segs, *poffset,
+ &copied);
+ total_read += copied;
+ }
+
+ /* resend call if it's a retryable error */
+ if (rc == -EAGAIN) {
+ rc = cifs_retry_async_readv(rdata);
+ goto restart_loop;
}
- } else {
- cifs_stats_bytes_read(pTcon, bytes_read);
- *poffset += bytes_read;
}
+ list_del_init(&rdata->list);
+ kref_put(&rdata->refcount, cifs_uncached_readdata_release);
}
- FreeXid(xid);
- return total_read;
+ cifs_stats_bytes_read(tcon, total_read);
+ *poffset += total_read;
+
+ return total_read ? total_read : rc;
}
ssize_t cifs_user_readv(struct kiocb *iocb, const struct iovec *iov,
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 08:47:34 +0000