Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756475Ab2JIR0n (ORCPT ); Tue, 9 Oct 2012 13:26:43 -0400 Received: from g1t0028.austin.hp.com ([15.216.28.35]:16085 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756337Ab2JIR0l (ORCPT ); Tue, 9 Oct 2012 13:26:41 -0400 Message-ID: <1349803595.3060.7.camel@lorien2> Subject: Re: [PATCH v5] dma-debug: New interfaces to debug dma mapping errors From: Shuah Khan Reply-To: shuah.khan@hp.com To: Konrad Rzeszutek Wilk 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 Date: Tue, 09 Oct 2012 11:26:35 -0600 In-Reply-To: <20121009171220.GJ31499@phenom.dumpdata.com> References: <1349716086.2674.20.camel@lorien2> <20121009171220.GJ31499@phenom.dumpdata.com> Organization: ISS-Linux Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9396 Lines: 244 On Tue, 2012-10-09 at 13:12 -0400, Konrad Rzeszutek Wilk wrote: > 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 Sorry, my bad. Thanks. > > --- > > 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/