Date: Wed, 14 Nov 2018 18:45:34 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r340441 - head/sys/x86/x86 Message-ID: <201811141845.wAEIjYwP075337@repo.freebsd.org>
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Author: jhb Date: Wed Nov 14 18:45:33 2018 New Revision: 340441 URL: https://svnweb.freebsd.org/changeset/base/340441 Log: Revert r332735 and fix MSI-X to properly fail allocations when full. The off-by-one errors in 332735 weren't actual errors and were preventing the last MSI interrupt source from being used. Instead, the issue is that when all MSI interrupt sources were allocated, the loop in msix_alloc() would terminate with 'msi' still set to non-null. The only check for 'i' overflowing was in the 'msi' == NULL case, so msix_alloc() would try to reuse the last MSI interrupt source instead of failing. Fix by moving the check for all sources being in use to just after the loop. Reviewed by: kib, markj MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D17976 Modified: head/sys/x86/x86/msi.c Modified: head/sys/x86/x86/msi.c ============================================================================== --- head/sys/x86/x86/msi.c Wed Nov 14 18:38:27 2018 (r340440) +++ head/sys/x86/x86/msi.c Wed Nov 14 18:45:33 2018 (r340441) @@ -409,7 +409,7 @@ again: /* Do we need to create some new sources? */ if (cnt < count) { /* If we would exceed the max, give up. */ - if (i + (count - cnt) >= first_msi_irq + NUM_MSI_INTS) { + if (i + (count - cnt) > first_msi_irq + NUM_MSI_INTS) { mtx_unlock(&msi_lock); free(mirqs, M_MSI); return (ENXIO); @@ -647,13 +647,14 @@ again: break; } + /* Are all IRQs in use? */ + if (i == first_msi_irq + NUM_MSI_INTS) { + mtx_unlock(&msi_lock); + return (ENXIO); + } + /* Do we need to create a new source? */ if (msi == NULL) { - /* If we would exceed the max, give up. */ - if (i + 1 >= first_msi_irq + NUM_MSI_INTS) { - mtx_unlock(&msi_lock); - return (ENXIO); - } mtx_unlock(&msi_lock); /* Create a new source. */
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