Commit bcd78e49 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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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, 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 <>
Tested-by: default avatarLawrence Greenfield <>
Cc: Christoph Rohland <>
Cc: Badari Pulavarty <>
Cc: Zach Brown <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 11fa977e
......@@ -1690,26 +1690,38 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
read_descriptor_t desc;
if ((ssize_t) count < 0)
return -EINVAL;
if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
if (!count)
return 0;
desc.written = 0;
desc.count = count;
desc.arg.buf = buf;
desc.error = 0;
do_shmem_file_read(filp, ppos, &desc, file_read_actor);
if (desc.written)
return desc.written;
return desc.error;
static ssize_t shmem_file_aio_read(struct kiocb *iocb,
const struct iovec *iov, unsigned long nr_segs, loff_t pos)
struct file *filp = iocb->ki_filp;
ssize_t retval;
unsigned long seg;
size_t count;
loff_t *ppos = &iocb->ki_pos;
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.arg.buf = iov[seg].iov_base;
desc.count = iov[seg].iov_len;
if (desc.count == 0)
desc.error = 0;
do_shmem_file_read(filp, ppos, &desc, file_read_actor);
retval += desc.written;
if (desc.error) {
retval = retval ?: desc.error;
if (desc.count > 0)
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,
.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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