9p: Make use of iounit for read/write

Change the v9fs_file_readn function to limit the maximum transfer size
based on the iounit or msize.

Also remove the redundant check for limiting the transfer size in
v9fs_file_write. This check is done by p9_client_write.

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 2bedc6c94fc2..2d686ec322a0 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -139,7 +139,7 @@ ssize_t
 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
                u64 offset)
 {
-        int n, total;
+        int n, total, size;
         struct p9_fid *fid = filp->private_data;
 
         P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
@@ -147,6 +147,7 @@ v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
 
         n = 0;
         total = 0;
+        size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
         do {
                 n = p9_client_read(fid, data, udata, offset, count);
                 if (n <= 0)
@@ -160,7 +161,7 @@ v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
                 offset += n;
                 count -= n;
                 total += n;
-        } while (count > 0 && n == (fid->clnt->msize - P9_IOHDRSZ));
+        } while (count > 0 && n == size);
 
         if (n < 0)
                 total = n;
@@ -183,11 +184,13 @@ v9fs_file_read(struct file *filp, char __user *udata, size_t count,
 {
         int ret;
         struct p9_fid *fid;
+        size_t size;
 
         P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
         fid = filp->private_data;
 
-        if (count > (fid->clnt->msize - P9_IOHDRSZ))
+        size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
+        if (count > size)
                 ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
         else
                 ret = p9_client_read(fid, NULL, udata, *offset, count);
@@ -224,9 +227,7 @@ v9fs_file_write(struct file *filp, const char __user * data,
         fid = filp->private_data;
         clnt = fid->clnt;
 
-        rsize = fid->iounit;
-        if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
-                rsize = clnt->msize - P9_IOHDRSZ;
+        rsize = fid->iounit ? fid->iounit : clnt->msize - P9_IOHDRSZ;
 
         do {
                 if (count < rsize)