/* * Copyright (c) 2000-2005 Silicon Graphics, Inc. * All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it would be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #include #include "kmem.h" #include "xfs_message.h" /* * Greedy allocation. May fail and may return vmalloced memory. */ void * kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize) { void *ptr; size_t kmsize = maxsize; while (!(ptr = vzalloc(kmsize))) { if ((kmsize >>= 1) <= minsize) kmsize = minsize; } if (ptr) *size = kmsize; return ptr; } void * kmem_alloc(size_t size, xfs_km_flags_t flags) { int retries = 0; gfp_t lflags = kmem_flags_convert(flags); void *ptr; do { ptr = kmalloc(size, lflags); if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP))) return ptr; if (!(++retries % 100)) xfs_err(NULL, "%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)", current->comm, current->pid, (unsigned int)size, __func__, lflags); congestion_wait(BLK_RW_ASYNC, HZ/50); } while (1); } void * kmem_zalloc_large(size_t size, xfs_km_flags_t flags) { unsigned noio_flag = 0; void *ptr; gfp_t lflags; ptr = kmem_zalloc(size, flags | KM_MAYFAIL); if (ptr) return ptr; /* * __vmalloc() will allocate data pages and auxillary structures (e.g. * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context * here. Hence we need to tell memory reclaim that we are in such a * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering * the filesystem here and potentially deadlocking. */ if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) noio_flag = memalloc_noio_save(); lflags = kmem_flags_convert(flags); ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL); if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS)) memalloc_noio_restore(noio_flag); return ptr; } void * kmem_realloc(const void *old, size_t newsize, xfs_km_flags_t flags) { int retries = 0; gfp_t lflags = kmem_flags_convert(flags); void *ptr; do { ptr = krealloc(old, newsize, lflags); if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP))) return ptr; if (!(++retries % 100)) xfs_err(NULL, "%s(%u) possible memory allocation deadlock size %zu in %s (mode:0x%x)", current->comm, current->pid, newsize, __func__, lflags); congestion_wait(BLK_RW_ASYNC, HZ/50); } while (1); } void * kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags) { int retries = 0; gfp_t lflags = kmem_flags_convert(flags); void *ptr; do { ptr = kmem_cache_alloc(zone, lflags); if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP))) return ptr; if (!(++retries % 100)) xfs_err(NULL, "%s(%u) possible memory allocation deadlock in %s (mode:0x%x)", current->comm, current->pid, __func__, lflags); congestion_wait(BLK_RW_ASYNC, HZ/50); } while (1); } akefile?h=nds-private-remove&id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>Makefile
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authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /net/sunrpc/xprtrdma/Makefile
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/Makefile')