From c45aa877256a4ec8f9a93a441d7041087cc0f8cf Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Tue, 11 Feb 2025 10:00:25 +0000 Subject: [PATCH] cifs: pick channels for individual subrequests commit f1bf10d7e909fe898a112f5cae1e97ce34d6484d upstream. The netfs library could break down a read request into multiple subrequests. When multichannel is used, there is potential to improve performance when each of these subrequests pick a different channel. Today we call cifs_pick_channel when the main read request is initialized in cifs_init_request. This change moves this to cifs_prepare_read, which is the right place to pick channel since it gets called for each subrequest. Interestingly cifs_prepare_write already does channel selection for individual subreq, but looks like it was missed for read. This is especially important when multichannel is used with increased rasize. In my test setup, with rasize set to 8MB, a sequential read of large file was taking 11.5s without this change. With the change, it completed in 9s. The difference is even more signigicant with bigger rasize. Cc: Cc: David Howells Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/cifsglob.h | 1 - fs/smb/client/file.c | 7 ++++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h index 94785abc9b1b2..05274121e46f0 100644 --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -1476,7 +1476,6 @@ struct cifs_io_parms { struct cifs_io_request { struct netfs_io_request rreq; struct cifsFileInfo *cfile; - struct TCP_Server_Info *server; pid_t pid; }; diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index a58a3333ecc30..313c851fc1c12 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -147,7 +147,7 @@ static int cifs_prepare_read(struct netfs_io_subrequest *subreq) struct netfs_io_request *rreq = subreq->rreq; struct cifs_io_subrequest *rdata = container_of(subreq, struct cifs_io_subrequest, subreq); struct cifs_io_request *req = container_of(subreq->rreq, struct cifs_io_request, rreq); - struct TCP_Server_Info *server = req->server; + struct TCP_Server_Info *server; struct cifs_sb_info *cifs_sb = CIFS_SB(rreq->inode->i_sb); size_t size; int rc = 0; @@ -156,6 +156,8 @@ static int cifs_prepare_read(struct netfs_io_subrequest *subreq) rdata->xid = get_xid(); rdata->have_xid = true; } + + server = cifs_pick_channel(tlink_tcon(req->cfile->tlink)->ses); rdata->server = server; if (cifs_sb->ctx->rsize == 0) @@ -198,7 +200,7 @@ static void cifs_issue_read(struct netfs_io_subrequest *subreq) struct netfs_io_request *rreq = subreq->rreq; struct cifs_io_subrequest *rdata = container_of(subreq, struct cifs_io_subrequest, subreq); struct cifs_io_request *req = container_of(subreq->rreq, struct cifs_io_request, rreq); - struct TCP_Server_Info *server = req->server; + struct TCP_Server_Info *server = rdata->server; int rc = 0; cifs_dbg(FYI, "%s: op=%08x[%x] mapping=%p len=%zu/%zu\n", @@ -265,7 +267,6 @@ static int cifs_init_request(struct netfs_io_request *rreq, struct file *file) open_file = file->private_data; rreq->netfs_priv = file->private_data; req->cfile = cifsFileInfo_get(open_file); - req->server = cifs_pick_channel(tlink_tcon(req->cfile->tlink)->ses); if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD) req->pid = req->cfile->pid; } else if (rreq->origin != NETFS_WRITEBACK) { -- 2.47.3