Some architectures enable sg chaining option while others do not. The requirement to enable sg chaining is that pages must be aligned at a 32-bit boundary in order to overload the LSB of the pointer. Regardless of whether ARCH_HAS_SG_CHAIN is defined or not, the above requirement is always chacked by BUG_ON() in sg_assign_page. So all architectures can enable sg chaining. As you can see from the changes in drivers/target/target_core_rd.c, enabling SG chaining for all architectures allows us to allocate discontiguous scatterlist tables which can be traversed throughout by sg_next() without a special handling for some architectures. Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: linux-arch@xxxxxxxxxxxxxxx Cc: "James E.J. Bottomley" <JBottomley@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: linux-scsi@xxxxxxxxxxxxxxx Cc: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> Cc: target-devel@xxxxxxxxxxxxxxx --- arch/arm/Kconfig | 6 ------ arch/arm64/Kconfig | 1 - arch/ia64/Kconfig | 1 - arch/powerpc/Kconfig | 1 - arch/s390/Kconfig | 1 - arch/sparc/Kconfig | 1 - arch/x86/Kconfig | 1 - drivers/target/target_core_rd.c | 45 ----------------------------------------- include/linux/scatterlist.h | 4 ---- include/scsi/scsi.h | 8 ++------ lib/Kconfig | 7 ------- lib/scatterlist.c | 8 -------- 12 files changed, 2 insertions(+), 82 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 45df48b..4436000 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -89,16 +89,11 @@ config ARM Europe. There is an ARM Linux project with a web page at <http://www.arm.linux.org.uk/>. -config ARM_HAS_SG_CHAIN - select ARCH_HAS_SG_CHAIN - bool - config NEED_SG_DMA_LENGTH bool config ARM_DMA_USE_IOMMU bool - select ARM_HAS_SG_CHAIN select NEED_SG_DMA_LENGTH if ARM_DMA_USE_IOMMU @@ -318,7 +313,6 @@ config ARCH_MULTIPLATFORM bool "Allow multiple platforms to be selected" depends on MMU select ARCH_WANT_OPTIONAL_GPIOLIB - select ARM_HAS_SG_CHAIN select ARM_PATCH_PHYS_VIRT select AUTO_ZRELADDR select CLKSRC_OF diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 4269dba..582462a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -5,7 +5,6 @@ config ARM64 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_GCOV_PROFILE_ALL - select ARCH_HAS_SG_CHAIN select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_USE_CMPXCHG_LOCKREF select ARCH_SUPPORTS_ATOMIC_RMW diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 76d25b2..a9f896e 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -32,7 +32,6 @@ config IA64 select HAVE_MEMBLOCK select HAVE_MEMBLOCK_NODE_MAP select HAVE_VIRT_CPU_ACCOUNTING - select ARCH_HAS_SG_CHAIN select VIRT_TO_BUS select ARCH_DISCARD_MEMBLOCK select GENERIC_IRQ_PROBE diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 190cc48..6f3b6768 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -112,7 +112,6 @@ config PPC select HAVE_DMA_API_DEBUG select HAVE_OPROFILE select HAVE_DEBUG_KMEMLEAK - select ARCH_HAS_SG_CHAIN select GENERIC_ATOMIC64 if PPC32 select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE select HAVE_PERF_EVENTS diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 8e58c61..2854e52 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -67,7 +67,6 @@ config S390 select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_GCOV_PROFILE_ALL - select ARCH_HAS_SG_CHAIN select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK select ARCH_INLINE_READ_LOCK_BH diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index e49502a..d0512f5 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -42,7 +42,6 @@ config SPARC select MODULES_USE_ELF_RELA select ODD_RT_SIGACTION select OLD_SIGSUSPEND - select ARCH_HAS_SG_CHAIN config SPARC32 def_bool !64BIT diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 226d569..eeb52b8 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -101,7 +101,6 @@ config X86 select HAVE_BPF_JIT if X86_64 select HAVE_ARCH_TRANSPARENT_HUGEPAGE select HAVE_ARCH_HUGE_VMAP if X86_64 || (X86_32 && X86_PAE) - select ARCH_HAS_SG_CHAIN select CLKEVT_I8253 select ARCH_HAVE_NMI_SAFE_CMPXCHG select GENERIC_IOMAP diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c index fa20d67..ce6a0ac 100644 --- a/drivers/target/target_core_rd.c +++ b/drivers/target/target_core_rd.c @@ -144,16 +144,12 @@ static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table * sg_per_table = (total_sg_needed > max_sg_per_table) ? max_sg_per_table : total_sg_needed; -#ifdef CONFIG_ARCH_HAS_SG_CHAIN - /* * Reserve extra element for chain entry */ if (sg_per_table < total_sg_needed) chain_entry = 1; -#endif /* CONFIG_ARCH_HAS_SG_CHAIN */ - sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg), GFP_KERNEL); if (!sg) { @@ -164,15 +160,11 @@ static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table * sg_init_table(sg, sg_per_table + chain_entry); -#ifdef CONFIG_ARCH_HAS_SG_CHAIN - if (i > 0) { sg_chain(sg_table[i - 1].sg_table, max_sg_per_table + 1, sg); } -#endif /* CONFIG_ARCH_HAS_SG_CHAIN */ - sg_table[i].sg_table = sg; sg_table[i].rd_sg_count = sg_per_table; sg_table[i].page_start_offset = page_offset; @@ -420,7 +412,6 @@ static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, dif_verify dif_verify) struct scatterlist *prot_sg; u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size; u32 prot_offset, prot_page; - u32 prot_npages __maybe_unused; u64 tmp; sense_reason_t rc = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; @@ -435,42 +426,6 @@ static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, dif_verify dif_verify) prot_sg = &prot_table->sg_table[prot_page - prot_table->page_start_offset]; -#ifndef CONFIG_ARCH_HAS_SG_CHAIN - - prot_npages = DIV_ROUND_UP(prot_offset + sectors * se_dev->prot_length, - PAGE_SIZE); - - /* - * Allocate temporaly contiguous scatterlist entries if prot pages - * straddles multiple scatterlist tables. - */ - if (prot_table->page_end_offset < prot_page + prot_npages - 1) { - int i; - - prot_sg = kcalloc(prot_npages, sizeof(*prot_sg), GFP_KERNEL); - if (!prot_sg) - return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; - - need_to_release = true; - sg_init_table(prot_sg, prot_npages); - - for (i = 0; i < prot_npages; i++) { - if (prot_page + i > prot_table->page_end_offset) { - prot_table = rd_get_prot_table(dev, - prot_page + i); - if (!prot_table) { - kfree(prot_sg); - return rc; - } - sg_unmark_end(&prot_sg[i - 1]); - } - prot_sg[i] = prot_table->sg_table[prot_page + i - - prot_table->page_start_offset]; - } - } - -#endif /* !CONFIG_ARCH_HAS_SG_CHAIN */ - rc = dif_verify(cmd, cmd->t_task_lba, sectors, 0, prot_sg, prot_offset); if (need_to_release) kfree(prot_sg); diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index ed8f9e7..bee59ea 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -136,10 +136,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, struct scatterlist *sgl) { -#ifndef CONFIG_ARCH_HAS_SG_CHAIN - BUG(); -#endif - /* * offset and length are unused for chain entry. Clear them. */ diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index d0a66aa..f01c5bb 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -28,14 +28,10 @@ enum scsi_timeouts { #define SCSI_MAX_SG_SEGMENTS 128 /* - * Like SCSI_MAX_SG_SEGMENTS, but for archs that have sg chaining. This limit - * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. + * This limit is totally arbitrary, a setting of 2048 will get you at least + * 8mb ios. */ -#ifdef CONFIG_ARCH_HAS_SG_CHAIN #define SCSI_MAX_SG_CHAIN_SEGMENTS 2048 -#else -#define SCSI_MAX_SG_CHAIN_SEGMENTS SCSI_MAX_SG_SEGMENTS -#endif /* * DIX-capable adapters effectively support infinite chaining for the diff --git a/lib/Kconfig b/lib/Kconfig index 601965a..0b938d2 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -515,11 +515,4 @@ config UCS2_STRING source "lib/fonts/Kconfig" -# -# sg chaining option -# - -config ARCH_HAS_SG_CHAIN - def_bool n - endmenu diff --git a/lib/scatterlist.c b/lib/scatterlist.c index c9f2e8c..6d9d477 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -73,16 +73,12 @@ EXPORT_SYMBOL(sg_nents); **/ struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) { -#ifndef CONFIG_ARCH_HAS_SG_CHAIN - struct scatterlist *ret = &sgl[nents - 1]; -#else struct scatterlist *sg, *ret = NULL; unsigned int i; for_each_sg(sgl, sg, nents, i) ret = sg; -#endif #ifdef CONFIG_DEBUG_SG BUG_ON(sgl[0].sg_magic != SG_MAGIC); BUG_ON(!sg_is_last(ret)); @@ -255,10 +251,6 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, if (nents == 0) return -EINVAL; -#ifndef CONFIG_ARCH_HAS_SG_CHAIN - if (WARN_ON_ONCE(nents > max_ents)) - return -EINVAL; -#endif left = nents; prv = NULL; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html