Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756450Ab2JIRYn (ORCPT ); Tue, 9 Oct 2012 13:24:43 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:46797 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756347Ab2JIRYk (ORCPT ); Tue, 9 Oct 2012 13:24:40 -0400 Date: Tue, 9 Oct 2012 13:12:20 -0400 From: Konrad Rzeszutek Wilk To: Shuah Khan Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, rob@landley.net, akpm@linux-foundation.org, stern@rowland.harvard.edu, joerg.roedel@amd.com, bhelgaas@google.com, LKML , linux-doc@vger.kernel.org, devel@linuxdriverproject.org, x86@kernel.org, shuahkhan@gmail.com Subject: Re: [PATCH v5] dma-debug: New interfaces to debug dma mapping errors Message-ID: <20121009171220.GJ31499@phenom.dumpdata.com> References: <1349716086.2674.20.camel@lorien2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1349716086.2674.20.camel@lorien2> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8839 Lines: 238 On Mon, Oct 08, 2012 at 11:08:06AM -0600, Shuah Khan wrote: > Add dma-debug interface debug_dma_mapping_error() to debug drivers that fail > to check dma mapping errors on addresses returned by dma_map_single() and > dma_map_page() interfaces. This interface clears a flag set by > debug_dma_map_page() to indicate that dma_mapping_error() has been called by > the driver. When driver does unmap, debug_dma_unmap() checks the flag and if > this flag is still set, prints warning message that includes call trace that > leads up to the unmap. This interface can be called from dma_mapping_error() > routines to enable dma mapping error check debugging. > > Tested: Intel iommu and swiotlb (iommu=soft) on x86-64 with > CONFIG_DMA_API_DEBUG enabled and disabled. > > Signed-off-by: Shuah Khan Not sure why it disappeared, but: Reviewed-by: Konrad Rzeszutek Wilk > --- > Documentation/DMA-API.txt | 12 ++++++ > arch/x86/include/asm/dma-mapping.h | 1 + > include/linux/dma-debug.h | 7 ++++ > lib/dma-debug.c | 71 ++++++++++++++++++++++++++++++++++-- > 4 files changed, 87 insertions(+), 4 deletions(-) > > diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt > index 66bd97a..78a6c56 100644 > --- a/Documentation/DMA-API.txt > +++ b/Documentation/DMA-API.txt > @@ -678,3 +678,15 @@ out of dma_debug_entries. These entries are preallocated at boot. The number > of preallocated entries is defined per architecture. If it is too low for you > boot with 'dma_debug_entries=' to overwrite the > architectural default. > + > +void debug_dmap_mapping_error(struct device *dev, dma_addr_t dma_addr); > + > +dma-debug interface debug_dma_mapping_error() to debug drivers that fail > +to check dma mapping errors on addresses returned by dma_map_single() and > +dma_map_page() interfaces. This interface clears a flag set by > +debug_dma_map_page() to indicate that dma_mapping_error() has been called by > +the driver. When driver does unmap, debug_dma_unmap() checks the flag and if > +this flag is still set, prints warning message that includes call trace that > +leads up to the unmap. This interface can be called from dma_mapping_error() > +routines to enable dma mapping error check debugging. > + > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h > index f7b4c79..808dae6 100644 > --- a/arch/x86/include/asm/dma-mapping.h > +++ b/arch/x86/include/asm/dma-mapping.h > @@ -47,6 +47,7 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev) > static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr) > { > struct dma_map_ops *ops = get_dma_ops(dev); > + debug_dma_mapping_error(dev, dma_addr); > if (ops->mapping_error) > return ops->mapping_error(dev, dma_addr); > > diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h > index 171ad8a..fc0e34c 100644 > --- a/include/linux/dma-debug.h > +++ b/include/linux/dma-debug.h > @@ -39,6 +39,8 @@ extern void debug_dma_map_page(struct device *dev, struct page *page, > int direction, dma_addr_t dma_addr, > bool map_single); > > +extern void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr); > + > extern void debug_dma_unmap_page(struct device *dev, dma_addr_t addr, > size_t size, int direction, bool map_single); > > @@ -105,6 +107,11 @@ static inline void debug_dma_map_page(struct device *dev, struct page *page, > { > } > > +static inline void debug_dma_mapping_error(struct device *dev, > + dma_addr_t dma_addr) > +{ > +} > + > static inline void debug_dma_unmap_page(struct device *dev, dma_addr_t addr, > size_t size, int direction, > bool map_single) > diff --git a/lib/dma-debug.c b/lib/dma-debug.c > index b9087bf..94aa94e 100644 > --- a/lib/dma-debug.c > +++ b/lib/dma-debug.c > @@ -45,6 +45,12 @@ enum { > dma_debug_coherent, > }; > > +enum map_err_types { > + MAP_ERR_CHECK_NOT_APPLICABLE, > + MAP_ERR_NOT_CHECKED, > + MAP_ERR_CHECKED, > +}; > + > #define DMA_DEBUG_STACKTRACE_ENTRIES 5 > > struct dma_debug_entry { > @@ -57,6 +63,7 @@ struct dma_debug_entry { > int direction; > int sg_call_ents; > int sg_mapped_ents; > + enum map_err_types map_err_type; > #ifdef CONFIG_STACKTRACE > struct stack_trace stacktrace; > unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES]; > @@ -114,6 +121,12 @@ static struct device_driver *current_driver __read_mostly; > > static DEFINE_RWLOCK(driver_name_lock); > > +static const char *const maperr2str[] = { > + [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable", > + [MAP_ERR_NOT_CHECKED] = "dma map error not checked", > + [MAP_ERR_CHECKED] = "dma map error checked", > +}; > + > static const char *type2name[4] = { "single", "page", > "scather-gather", "coherent" }; > > @@ -376,11 +389,12 @@ void debug_dma_dump_mappings(struct device *dev) > list_for_each_entry(entry, &bucket->list, list) { > if (!dev || dev == entry->dev) { > dev_info(entry->dev, > - "%s idx %d P=%Lx D=%Lx L=%Lx %s\n", > + "%s idx %d P=%Lx D=%Lx L=%Lx %s %s\n", > type2name[entry->type], idx, > (unsigned long long)entry->paddr, > entry->dev_addr, entry->size, > - dir2name[entry->direction]); > + dir2name[entry->direction], > + maperr2str[entry->map_err_type]); > } > } > > @@ -838,13 +852,28 @@ static __init int dma_debug_entries_cmdline(char *str) > __setup("dma_debug=", dma_debug_cmdline); > __setup("dma_debug_entries=", dma_debug_entries_cmdline); > > +/* Calling dma_mapping_error() from dma-debug api will result in calling > + debug_dma_mapping_error() - need internal mapping error routine to > + avoid debug checks */ > +#ifndef DMA_ERROR_CODE > +#define DMA_ERROR_CODE 0 > +#endif > +static inline int has_mapping_error(struct device *dev, dma_addr_t dma_addr) > +{ > + const struct dma_map_ops *ops = get_dma_ops(dev); > + if (ops->mapping_error) > + return ops->mapping_error(dev, dma_addr); > + > + return (dma_addr == DMA_ERROR_CODE); > +} > + > static void check_unmap(struct dma_debug_entry *ref) > { > struct dma_debug_entry *entry; > struct hash_bucket *bucket; > unsigned long flags; > > - if (dma_mapping_error(ref->dev, ref->dev_addr)) { > + if (unlikely(has_mapping_error(ref->dev, ref->dev_addr))) { > err_printk(ref->dev, NULL, "DMA-API: device driver tries " > "to free an invalid DMA memory address\n"); > return; > @@ -910,6 +939,15 @@ static void check_unmap(struct dma_debug_entry *ref) > dir2name[ref->direction]); > } > > + if (entry->map_err_type == MAP_ERR_NOT_CHECKED) { > + err_printk(ref->dev, entry, > + "DMA-API: device driver failed to check map error" > + "[device address=0x%016llx] [size=%llu bytes] " > + "[mapped as %s]", > + ref->dev_addr, ref->size, > + type2name[entry->type]); > + } > + > hash_bucket_del(entry); > dma_entry_free(entry); > > @@ -1017,7 +1055,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, > if (unlikely(global_disable)) > return; > > - if (unlikely(dma_mapping_error(dev, dma_addr))) > + if (unlikely(has_mapping_error(dev, dma_addr))) > return; > > entry = dma_entry_alloc(); > @@ -1030,6 +1068,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, > entry->dev_addr = dma_addr; > entry->size = size; > entry->direction = direction; > + entry->map_err_type = MAP_ERR_NOT_CHECKED; > > if (map_single) > entry->type = dma_debug_single; > @@ -1045,6 +1084,30 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, > } > EXPORT_SYMBOL(debug_dma_map_page); > > +void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) > +{ > + struct dma_debug_entry ref; > + struct dma_debug_entry *entry; > + struct hash_bucket *bucket; > + unsigned long flags; > + > + if (unlikely(global_disable)) > + return; > + > + ref.dev = dev; > + ref.dev_addr = dma_addr; > + bucket = get_hash_bucket(&ref, &flags); > + entry = bucket_find_exact(bucket, &ref); > + > + if (!entry) > + goto out; > + > + entry->map_err_type = MAP_ERR_CHECKED; > +out: > + put_hash_bucket(bucket, &flags); > +} > +EXPORT_SYMBOL(debug_dma_mapping_error); > + > void debug_dma_unmap_page(struct device *dev, dma_addr_t addr, > size_t size, int direction, bool map_single) > { > -- > 1.7.9.5 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/