CIFS: Separate filling pages from iovec write (66386c08) · Commits · 戴 / test

fs/cifs/file.c

+50 −34

Original line number	Diff line number	Diff line
		@@ -2423,11 +2423,53 @@ cifs_uncached_retry_writev(struct cifs_writedata *wdata)
		return rc;
		}

		static int
		wdata_fill_from_iovec(struct cifs_writedata wdata, struct iov_iter from,
		size_t len, unsigned long num_pages)
		{
		size_t save_len, copied, bytes, cur_len = *len;
		unsigned long i, nr_pages = *num_pages;

		save_len = cur_len;
		for (i = 0; i < nr_pages; i++) {
		bytes = min_t(const size_t, cur_len, PAGE_SIZE);
		copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
		cur_len -= copied;
		/*
		* If we didn't copy as much as we expected, then that
		* may mean we trod into an unmapped area. Stop copying
		* at that point. On the next pass through the big
		* loop, we'll likely end up getting a zero-length
		* write and bailing out of it.
		*/
		if (copied < bytes)
		break;
		}
		cur_len = save_len - cur_len;
		*len = cur_len;

		/*
		* If we have no data to send, then that probably means that
		* the copy above failed altogether. That's most likely because
		* the address in the iovec was bogus. Return -EFAULT and let
		* the caller free anything we allocated and bail out.
		*/
		if (!cur_len)
		return -EFAULT;

		/*
		* i + 1 now represents the number of pages we actually used in
		* the copy phase above.
		*/
		*num_pages = i + 1;
		return 0;
		}

		static ssize_t
		cifs_iovec_write(struct file file, struct iov_iter from, loff_t *poffset)
		{
		unsigned long nr_pages, i;
		size_t bytes, copied, len, cur_len;
		unsigned long nr_pages, num_pages, i;
		size_t len, cur_len;
		ssize_t total_written = 0;
		loff_t offset;
		struct cifsFileInfo *open_file;
		@@ -2464,8 +2506,6 @@ cifs_iovec_write(struct file file, struct iov_iter from, loff_t *poffset)
		pid = current->tgid;

		do {
		size_t save_len;

		nr_pages = get_numpages(cifs_sb->wsize, len, &cur_len);
		wdata = cifs_writedata_alloc(nr_pages,
		cifs_uncached_writev_complete);
		@@ -2480,44 +2520,20 @@ cifs_iovec_write(struct file file, struct iov_iter from, loff_t *poffset)
		break;
		}

		save_len = cur_len;
		for (i = 0; i < nr_pages; i++) {
		bytes = min_t(size_t, cur_len, PAGE_SIZE);
		copied = copy_page_from_iter(wdata->pages[i], 0, bytes,
		from);
		cur_len -= copied;
		/*
		* If we didn't copy as much as we expected, then that
		* may mean we trod into an unmapped area. Stop copying
		* at that point. On the next pass through the big
		* loop, we'll likely end up getting a zero-length
		* write and bailing out of it.
		*/
		if (copied < bytes)
		break;
		}
		cur_len = save_len - cur_len;

		/*
		* If we have no data to send, then that probably means that
		* the copy above failed altogether. That's most likely because
		* the address in the iovec was bogus. Set the rc to -EFAULT,
		* free anything we allocated and bail out.
		*/
		if (!cur_len) {
		num_pages = nr_pages;
		rc = wdata_fill_from_iovec(wdata, from, &cur_len, &num_pages);
		if (rc) {
		for (i = 0; i < nr_pages; i++)
		put_page(wdata->pages[i]);
		kfree(wdata);
		rc = -EFAULT;
		break;
		}

		/*
		* i + 1 now represents the number of pages we actually used in
		* the copy phase above. Bring nr_pages down to that, and free
		* any pages that we didn't use.
		* Bring nr_pages down to the number of pages we actually used,
		* and free any pages that we didn't use.
		*/
		for ( ; nr_pages > i + 1; nr_pages--)
		for ( ; nr_pages > num_pages; nr_pages--)
		put_page(wdata->pages[nr_pages - 1]);

		wdata->sync_mode = WB_SYNC_ALL;

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