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author | Al Viro <viro@zeniv.linux.org.uk> | 2014-02-04 14:07:43 -0500 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-04-01 23:19:23 -0400 |
commit | 7f25bba819a38ab7310024a9350655f374707e20 (patch) | |
tree | d93d7fcf6db340dc8078b18555d0abb4611ef488 | |
parent | 6130f5315ee80a591285a25957af71621bd0f17e (diff) | |
download | op-kernel-dev-7f25bba819a38ab7310024a9350655f374707e20.zip op-kernel-dev-7f25bba819a38ab7310024a9350655f374707e20.tar.gz |
cifs_iovec_read: keep iov_iter between the calls of cifs_readdata_to_iov()
... we are doing them on adjacent parts of file, so what happens is that
each subsequent call works to rebuild the iov_iter to exact state it
had been abandoned in by previous one. Just keep it through the entire
cifs_iovec_read(). And use copy_page_to_iter() instead of doing
kmap/copy_to_user/kunmap manually...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r-- | fs/cifs/file.c | 62 |
1 files changed, 17 insertions, 45 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index df414db..ad63e47 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2727,56 +2727,27 @@ cifs_retry_async_readv(struct cifs_readdata *rdata) /** * 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 + * @iter: destination for our data * * 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) +static int +cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter) { - int rc = 0; - struct iov_iter ii; - size_t pos = rdata->offset - offset; - ssize_t remaining = rdata->bytes; - unsigned char *pdata; + size_t remaining = rdata->bytes; unsigned int i; - /* 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; for (i = 0; i < rdata->nr_pages; i++) { - ssize_t copy; struct page *page = rdata->pages[i]; - - /* 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); - } - } + size_t copy = min(remaining, PAGE_SIZE); + size_t written = copy_page_to_iter(page, 0, copy, iter); + remaining -= written; + if (written < copy && iov_iter_count(iter) > 0) + break; } - - return rc; + return remaining ? -EFAULT : 0; } static void @@ -2851,6 +2822,7 @@ cifs_iovec_read(struct file *file, const struct iovec *iov, struct cifsFileInfo *open_file; struct cifs_readdata *rdata, *tmp; struct list_head rdata_list; + struct iov_iter to; pid_t pid; if (!nr_segs) @@ -2860,6 +2832,8 @@ cifs_iovec_read(struct file *file, const struct iovec *iov, if (!len) return 0; + iov_iter_init(&to, iov, nr_segs, len, 0); + INIT_LIST_HEAD(&rdata_list); cifs_sb = CIFS_SB(file->f_path.dentry->d_sb); open_file = file->private_data; @@ -2917,12 +2891,11 @@ error: if (!list_empty(&rdata_list)) rc = 0; + len = iov_iter_count(&to); /* the loop below should proceed in the order of increasing offsets */ list_for_each_entry_safe(rdata, tmp, &rdata_list, list) { again: if (!rc) { - ssize_t copied; - /* FIXME: freezable sleep too? */ rc = wait_for_completion_killable(&rdata->done); if (rc) @@ -2935,10 +2908,7 @@ error: goto again; } } else { - rc = cifs_readdata_to_iov(rdata, iov, - nr_segs, *poffset, - &copied); - total_read += copied; + rc = cifs_readdata_to_iov(rdata, &to); } } @@ -2946,6 +2916,8 @@ error: kref_put(&rdata->refcount, cifs_uncached_readdata_release); } + total_read = len - iov_iter_count(&to); + cifs_stats_bytes_read(tcon, total_read); *poffset += total_read; |