Re: Spinlocking patch for in xprt.c
> " " == David S Miller <[EMAIL PROTECTED]> writes: > Trond, did you actually look at how this code works before you > made modifications to my fixes? > xprt_lock serializes sleep/wakeup sequences in the xprt code, > so you cannot remove xprt_lock from the sections where I added > holding of xprt_sock_lock to protect the state of > xprt->snd_task. So for example, this part of your patch is > completely bogus and will create new corruptions and crashes: IIRC xprt_lock is there for 2 purposes: - serialize access to the TCP connect code - gate access to the *socket* via the xprt_(up|down)_transmit() (and hence setting xprt->snd_task which is a pointer to the task that currently is allowed to access the socket.) Those 2 tasks are completely orthogonal to one another, so we should be quite free to drop xprt_lock in the second case. I can see no other places where we're using xprt_lock to protect a sleep/wakeup of xprt->snd_task unless you're introducing it? If so for what purpose? Cheers, Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: Spinlocking patch for in xprt.c
" " == David S Miller [EMAIL PROTECTED] writes: Trond, did you actually look at how this code works before you made modifications to my fixes? xprt_lock serializes sleep/wakeup sequences in the xprt code, so you cannot remove xprt_lock from the sections where I added holding of xprt_sock_lock to protect the state of xprt-snd_task. So for example, this part of your patch is completely bogus and will create new corruptions and crashes: IIRC xprt_lock is there for 2 purposes: - serialize access to the TCP connect code - gate access to the *socket* via the xprt_(up|down)_transmit() (and hence setting xprt-snd_task which is a pointer to the task that currently is allowed to access the socket.) Those 2 tasks are completely orthogonal to one another, so we should be quite free to drop xprt_lock in the second case. I can see no other places where we're using xprt_lock to protect a sleep/wakeup of xprt-snd_task unless you're introducing it? If so for what purpose? Cheers, Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: Spinlocking patch for in xprt.c
Trond, did you actually look at how this code works before you made modifications to my fixes? xprt_lock serializes sleep/wakeup sequences in the xprt code, so you cannot remove xprt_lock from the sections where I added holding of xprt_sock_lock to protect the state of xprt->snd_task. So for example, this part of your patch is completely bogus and will create new corruptions and crashes: @@ -1143,10 +1143,10 @@ struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; if (xprt->snd_task && xprt->snd_task == task) { - spin_lock(_lock); + spin_lock_bh(_sock_lock); xprt->snd_task = NULL; rpc_wake_up_next(>sending); - spin_unlock(_lock); + spin_unlock_bh(_sock_lock); } } You _must_ hold both xprt_lock and xprt_sock_lock in this section of code, not just one or just the other. Linus, please do not apply this patch until these issues are addressed. Later, David S. Miller [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: Spinlocking patch for in xprt.c
Trond, did you actually look at how this code works before you made modifications to my fixes? xprt_lock serializes sleep/wakeup sequences in the xprt code, so you cannot remove xprt_lock from the sections where I added holding of xprt_sock_lock to protect the state of xprt-snd_task. So for example, this part of your patch is completely bogus and will create new corruptions and crashes: @@ -1143,10 +1143,10 @@ struct rpc_xprt *xprt = task-tk_rqstp-rq_xprt; if (xprt-snd_task xprt-snd_task == task) { - spin_lock(xprt_lock); + spin_lock_bh(xprt_sock_lock); xprt-snd_task = NULL; rpc_wake_up_next(xprt-sending); - spin_unlock(xprt_lock); + spin_unlock_bh(xprt_sock_lock); } } You _must_ hold both xprt_lock and xprt_sock_lock in this section of code, not just one or just the other. Linus, please do not apply this patch until these issues are addressed. Later, David S. Miller [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Spinlocking patch for in xprt.c
The following patch (taken from the zero copy networking) upgrades the spinlocking of the xprt_(up|down)_transmit() 'semaphores' in order to work safely with the networking bottom halves. Several of the latter (cf. xprt.c:tcp_write_space() & friends) do want to test the value of 'xprt->snd_task'. Cheers, Trond diff -u --recursive --new-file linux-2.4.1-fh_align/net/sunrpc/xprt.c linux-2.4.1-xprt/net/sunrpc/xprt.c --- linux-2.4.1-fh_align/net/sunrpc/xprt.c Wed Nov 29 07:34:01 2000 +++ linux-2.4.1-xprt/net/sunrpc/xprt.c Fri Jan 12 11:58:42 2001 @@ -1116,7 +1116,7 @@ struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; struct rpc_rqst *req = task->tk_rqstp; - spin_lock(_lock); + spin_lock_bh(_sock_lock); if (xprt->snd_task && xprt->snd_task != task) { dprintk("RPC: %4d TCP write queue full (task %d)\n", task->tk_pid, xprt->snd_task->tk_pid); @@ -1130,7 +1130,7 @@ #endif req->rq_bytes_sent = 0; } - spin_unlock(_lock); + spin_unlock_bh(_sock_lock); return xprt->snd_task == task; } @@ -1143,10 +1143,10 @@ struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt; if (xprt->snd_task && xprt->snd_task == task) { - spin_lock(_lock); + spin_lock_bh(_sock_lock); xprt->snd_task = NULL; rpc_wake_up_next(>sending); - spin_unlock(_lock); + spin_unlock_bh(_sock_lock); } } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Spinlocking patch for in xprt.c
The following patch (taken from the zero copy networking) upgrades the spinlocking of the xprt_(up|down)_transmit() 'semaphores' in order to work safely with the networking bottom halves. Several of the latter (cf. xprt.c:tcp_write_space() friends) do want to test the value of 'xprt-snd_task'. Cheers, Trond diff -u --recursive --new-file linux-2.4.1-fh_align/net/sunrpc/xprt.c linux-2.4.1-xprt/net/sunrpc/xprt.c --- linux-2.4.1-fh_align/net/sunrpc/xprt.c Wed Nov 29 07:34:01 2000 +++ linux-2.4.1-xprt/net/sunrpc/xprt.c Fri Jan 12 11:58:42 2001 @@ -1116,7 +1116,7 @@ struct rpc_xprt *xprt = task-tk_rqstp-rq_xprt; struct rpc_rqst *req = task-tk_rqstp; - spin_lock(xprt_lock); + spin_lock_bh(xprt_sock_lock); if (xprt-snd_task xprt-snd_task != task) { dprintk("RPC: %4d TCP write queue full (task %d)\n", task-tk_pid, xprt-snd_task-tk_pid); @@ -1130,7 +1130,7 @@ #endif req-rq_bytes_sent = 0; } - spin_unlock(xprt_lock); + spin_unlock_bh(xprt_sock_lock); return xprt-snd_task == task; } @@ -1143,10 +1143,10 @@ struct rpc_xprt *xprt = task-tk_rqstp-rq_xprt; if (xprt-snd_task xprt-snd_task == task) { - spin_lock(xprt_lock); + spin_lock_bh(xprt_sock_lock); xprt-snd_task = NULL; rpc_wake_up_next(xprt-sending); - spin_unlock(xprt_lock); + spin_unlock_bh(xprt_sock_lock); } } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/