Date: Thu, 30 Jan 2020 12:04:03 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r357293 - head/sys/net Message-ID: <202001301204.00UC43Rw022059@repo.freebsd.org>
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Author: hselasky Date: Thu Jan 30 12:04:02 2020 New Revision: 357293 URL: https://svnweb.freebsd.org/changeset/base/357293 Log: Widen EPOCH(9) usage in netisr. Software interrupt handlers are allowed to sleep. In swi_net() there is a read lock behind NETISR_RLOCK() which in turn ends up calling msleep() which means the whole of swi_net() cannot be protected by an EPOCH(9) section. By default the NETISR_LOCKING feature is disabled. This issue was introduced by r357004. This is a preparation step for replacing the functionality provided by r357004. Found by: kib@ Sponsored by: Mellanox Technologies Modified: head/sys/net/netisr.c Modified: head/sys/net/netisr.c ============================================================================== --- head/sys/net/netisr.c Thu Jan 30 10:40:38 2020 (r357292) +++ head/sys/net/netisr.c Thu Jan 30 12:04:02 2020 (r357293) @@ -920,6 +920,7 @@ netisr_process_workstream_proto(struct netisr_workstre static void swi_net(void *arg) { + struct epoch_tracker et; #ifdef NETISR_LOCKING struct rm_priotracker tracker; #endif @@ -931,7 +932,9 @@ swi_net(void *arg) #ifdef DEVICE_POLLING KASSERT(nws_count == 1, ("%s: device_polling but nws_count != 1", __func__)); + NET_EPOCH_ENTER(et); netisr_poll(); + NET_EPOCH_EXIT(et); #endif #ifdef NETISR_LOCKING NETISR_RLOCK(&tracker); @@ -940,6 +943,7 @@ swi_net(void *arg) KASSERT(!(nwsp->nws_flags & NWS_RUNNING), ("swi_net: running")); if (nwsp->nws_flags & NWS_DISPATCHING) goto out; + NET_EPOCH_ENTER(et); nwsp->nws_flags |= NWS_RUNNING; nwsp->nws_flags &= ~NWS_SCHEDULED; while ((bits = nwsp->nws_pendingbits) != 0) { @@ -950,6 +954,7 @@ swi_net(void *arg) } } nwsp->nws_flags &= ~NWS_RUNNING; + NET_EPOCH_EXIT(et); out: NWS_UNLOCK(nwsp); #ifdef NETISR_LOCKING
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