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: Hugh Dickins <hugh@veritas.com> Tested-by: Lawrence 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 30 additions and 17 deletions
47
mm/shmem.c
47
mm/shmem.c
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@ -1690,26 +1690,38 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
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file_accessed(filp);
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}
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static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
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static ssize_t shmem_file_aio_read(struct kiocb *iocb,
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const struct iovec *iov, unsigned long nr_segs, loff_t pos)
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{
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read_descriptor_t desc;
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struct file *filp = iocb->ki_filp;
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ssize_t retval;
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unsigned long seg;
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size_t count;
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loff_t *ppos = &iocb->ki_pos;
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if ((ssize_t) count < 0)
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return -EINVAL;
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if (!access_ok(VERIFY_WRITE, buf, count))
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return -EFAULT;
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if (!count)
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return 0;
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retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
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if (retval)
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return retval;
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desc.written = 0;
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desc.count = count;
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desc.arg.buf = buf;
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desc.error = 0;
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for (seg = 0; seg < nr_segs; seg++) {
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read_descriptor_t desc;
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do_shmem_file_read(filp, ppos, &desc, file_read_actor);
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if (desc.written)
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return desc.written;
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return desc.error;
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desc.written = 0;
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desc.arg.buf = iov[seg].iov_base;
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desc.count = iov[seg].iov_len;
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if (desc.count == 0)
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continue;
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desc.error = 0;
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do_shmem_file_read(filp, ppos, &desc, file_read_actor);
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retval += desc.written;
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if (desc.error) {
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retval = retval ?: desc.error;
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break;
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}
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if (desc.count > 0)
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break;
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}
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return retval;
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}
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static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
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@ -2369,8 +2381,9 @@ static const struct file_operations shmem_file_operations = {
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.mmap = shmem_mmap,
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#ifdef CONFIG_TMPFS
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.llseek = generic_file_llseek,
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.read = shmem_file_read,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = shmem_file_aio_read,
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.aio_write = generic_file_aio_write,
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.fsync = simple_sync_file,
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.splice_read = generic_file_splice_read,
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