Commit bcd78e49 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

tmpfs: support aio 



We have a request for tmpfs to support the AIO interface: easily done, no
more than replacing the old shmem_file_read by shmem_file_aio_read,
cribbed from generic_file_aio_read.  (In 2.6.25 its write side was already
changed to use generic_file_aio_write.)

Incorporate cleanups from Andrew Morton and Harvey Harrison.

Tests out fine with LTP's ltp-aiodio.sh, given hacks (not included) to
support O_DIRECT.  tmpfs cannot honestly support O_DIRECT: its
cache-avoiding-IO nature is at odds with direct IO-avoiding-cache.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Tested-by: default avatarLawrence Greenfield <leg@google.com>
Cc: Christoph Rohland <hans-christoph.rohland@sap.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 11fa977e

mm/shmem.c

+34 −21
Original line number Diff line number Diff line
@@ -1690,26 +1690,38 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_ 
	file_accessed(filp);

}



static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)

static ssize_t shmem_file_aio_read(struct kiocb *iocb,

		const struct iovec *iov, unsigned long nr_segs, loff_t pos)

{

	read_descriptor_t desc;

	struct file *filp = iocb->ki_filp;

	ssize_t retval;

	unsigned long seg;

	size_t count;

	loff_t *ppos = &iocb->ki_pos;



	if ((ssize_t) count < 0)

		return -EINVAL;

	if (!access_ok(VERIFY_WRITE, buf, count))

		return -EFAULT;

	if (!count)

		return 0;

	retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);

	if (retval)

		return retval;



	for (seg = 0; seg < nr_segs; seg++) {

		read_descriptor_t desc;



		desc.written = 0;

	desc.count = count;

	desc.arg.buf = buf;

		desc.arg.buf = iov[seg].iov_base;

		desc.count = iov[seg].iov_len;

		if (desc.count == 0)

			continue;

		desc.error = 0;



		do_shmem_file_read(filp, ppos, &desc, file_read_actor);

	if (desc.written)

		return desc.written;

	return desc.error;

		retval += desc.written;

		if (desc.error) {

			retval = retval ?: desc.error;

			break;

		}

		if (desc.count > 0)

			break;

	}

	return retval;

}



static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
@@ -2369,8 +2381,9 @@ static const struct file_operations shmem_file_operations = { 
	.mmap		= shmem_mmap,

#ifdef CONFIG_TMPFS

	.llseek		= generic_file_llseek,

	.read		= shmem_file_read,

	.read		= do_sync_read,

	.write		= do_sync_write,

	.aio_read	= shmem_file_aio_read,

	.aio_write	= generic_file_aio_write,

	.fsync		= simple_sync_file,

	.splice_read	= generic_file_splice_read,

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