dax: Report bytes remaining in dax_iomap_actor() (a77d4786) · Commits · 戴 / test

In preparation for protecting the dax read(2) path from media errors with copy_to_iter_mcsafe() (via dax_copy_to_iter()), convert the implementation to report the bytes successfully transferred. Cc: <x86@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:

Dan Williams <dan.j.williams@intel.com>

fs/dax.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -991,6 +991,7 @@ dax_iomap_actor(struct inode inode, loff_t pos, loff_t length, void data,
		struct iov_iter *iter = data;
		loff_t end = pos + length, done = 0;
		ssize_t ret = 0;
		size_t xfer;
		int id;

		if (iov_iter_rw(iter) == READ) {
		@@ -1054,19 +1055,20 @@ dax_iomap_actor(struct inode inode, loff_t pos, loff_t length, void data,
		* vfs_write(), depending on which operation we are doing.
		*/
		if (iov_iter_rw(iter) == WRITE)
		map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr,
		xfer = dax_copy_from_iter(dax_dev, pgoff, kaddr,
		map_len, iter);
		else
		map_len = dax_copy_to_iter(dax_dev, pgoff, kaddr,
		xfer = dax_copy_to_iter(dax_dev, pgoff, kaddr,
		map_len, iter);
		if (map_len <= 0) {
		ret = map_len ? map_len : -EFAULT;
		break;
		}

		pos += map_len;
		length -= map_len;
		done += map_len;
		pos += xfer;
		length -= xfer;
		done += xfer;

		if (xfer == 0)
		ret = -EFAULT;
		if (xfer < map_len)
		break;
		}
		dax_read_unlock(id);

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