On Mon, 01 Oct 2012 13:10:45 +0530
Suresh Jayaraman <sjayaraman@xxxxxxxx> wrote:
> In smb_sendv(), we seem to retry if kernel_sendmsg() returned either
> -ENOSPC or -EAGAIN. In either case after multiple attempts, we set the
> error to -EAGAIN before breaking out of the loop.
>
> First, it is not clear to me when kernel_sendmsg() can return -ENOSPC,
> and what it would mean and why should we retry. It makes me wonder
> whether this check is part of some old code. Also, there seem to be no
> need to set the error back to -EAGAIN before we break out the loop.
> Fix this by making cifs retry only if kernel_sendmsg() returns -EAGAIN.
>
> If the above discussion make sense, here is a patch to fix this.
> ---
>
> Retry kernel_sendmsg() only in case of -EAGAIN and remove redundant
> error assignment.
>
>
> Signed-off-by: Suresh Jayaraman <sjayaraman@xxxxxxxx>
> ---
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index d9b639b..a33db4c 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -154,7 +154,7 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> while (total_len) {
> rc = kernel_sendmsg(ssocket, &smb_msg, &iov[first_vec],
> n_vec - first_vec, total_len);
> - if ((rc == -ENOSPC) || (rc == -EAGAIN)) {
> + if (rc == -EAGAIN) {
> i++;
> /*
> * If blocking send we try 3 times, since each can block
> @@ -177,7 +177,6 @@ smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
> if ((i >= 14) || (!server->noblocksnd && (i > 2))) {
> cERROR(1, "sends on sock %p stuck for 15 seconds",
> ssocket);
> - rc = -EAGAIN;
> break;
> }
> msleep(1 << i);
> --
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That ENOSPC has been there a long time, and I think you're correct that
it's of questionable value.
Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
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