From 87fb9ed200f49db51f2ced578647a3529c1105dc Mon Sep 17 00:00:00 2001 From: Thanos Makatos Date: Thu, 5 Sep 2019 09:51:16 -0400 Subject: remove unnecessary loop for retrieving region Signed-off-by: Thanos Makatos --- lib/libmuser.c | 39 +++++++++++++++++++-------------------- lib/libmuser_pci.c | 4 ++-- lib/muser.h | 6 ++---- lib/muser_priv.h | 2 +- 4 files changed, 24 insertions(+), 27 deletions(-) (limited to 'lib') diff --git a/lib/libmuser.c b/lib/libmuser.c index 95d24a0..f9ce245 100644 --- a/lib/libmuser.c +++ b/lib/libmuser.c @@ -418,13 +418,20 @@ dev_get_sparse_mmap_cap(lm_ctx_t *lm_ctx, lm_reg_info_t *lm_reg, } #define LM_REGION_SHIFT 40 +#define LM_REGION_MASK ((1ULL << LM_REGION_SHIFT) - 1) uint64_t -region_offset(const uint32_t region) +region_to_offset(const uint32_t region) { return (uint64_t)region << LM_REGION_SHIFT; } +uint32_t +offset_to_region(const uint64_t offset) +{ + return (offset >> LM_REGION_SHIFT) & LM_REGION_MASK; +} + static long dev_get_reginfo(lm_ctx_t * lm_ctx, struct vfio_region_info *vfio_reg) { @@ -441,7 +448,7 @@ dev_get_reginfo(lm_ctx_t * lm_ctx, struct vfio_region_info *vfio_reg) return -EINVAL; } - vfio_reg->offset = region_offset(vfio_reg->index); + vfio_reg->offset = region_to_offset(vfio_reg->index); vfio_reg->flags = lm_reg->flags; vfio_reg->size = lm_reg->size; @@ -573,7 +580,7 @@ static int muser_mmap(lm_ctx_t * lm_ctx, struct muser_cmd *cmd) unsigned long len = cmd->mmap.request.len; unsigned long pgoff = cmd->mmap.request.pgoff; - region = lm_get_region(lm_ctx, pgoff, len, &pgoff); + region = lm_get_region(pgoff, len, &pgoff); if (region < 0) { lm_log(lm_ctx, LM_ERR, "bad region %d\n", region); err = region; @@ -630,26 +637,18 @@ post_read(lm_ctx_t * const lm_ctx, struct muser_cmd *const cmd, ssize_t ret) } int -lm_get_region(lm_ctx_t * const lm_ctx, const loff_t pos, const size_t count, - loff_t * const off) +lm_get_region(const loff_t pos, const size_t count, loff_t * const off) { - assert(lm_ctx); - assert(off); - lm_pci_info_t *pci_info = &lm_ctx->pci_info; + int r; - int i; + assert(off); - for (i = 0; i < LM_DEV_NUM_REGS; i++) { - const lm_reg_info_t * const reg_info = &pci_info->reg_info[i]; - const uint64_t _region_offset = region_offset(i); - if (pos >= _region_offset) { - if (pos - _region_offset + count <= reg_info->size) { - *off = pos - _region_offset; - return i; - } - } + r = offset_to_region(pos); + if (offset_to_region(pos + count) != r) { + return -ENOENT; } - return -ENOENT; + *off = pos - region_to_offset(r); + return r; } static ssize_t @@ -689,7 +688,7 @@ do_access(lm_ctx_t * const lm_ctx, char * const buf, size_t count, loff_t pos, assert(count > 0); pci_info = &lm_ctx->pci_info; - idx = lm_get_region(lm_ctx, pos, count, &offset); + idx = lm_get_region(pos, count, &offset); if (idx < 0) { lm_log(lm_ctx, LM_ERR, "invalid region %d\n", idx); return idx; diff --git a/lib/libmuser_pci.c b/lib/libmuser_pci.c index 7131e94..488167d 100644 --- a/lib/libmuser_pci.c +++ b/lib/libmuser_pci.c @@ -275,7 +275,7 @@ muser_do_pci_hdr_access(lm_ctx_t * const lm_ctx, size_t * const count, assert(pos); assert(buf); - _pos = *pos - region_offset(LM_DEV_CFG_REG_IDX); + _pos = *pos - region_to_offset(LM_DEV_CFG_REG_IDX); _count = MIN(*count, PCI_STD_HEADER_SIZEOF - _pos); if (is_write) { @@ -291,7 +291,7 @@ muser_do_pci_hdr_access(lm_ctx_t * const lm_ctx, size_t * const count, static inline bool muser_is_pci_hdr_access(const lm_reg_info_t * const reg_info, const loff_t pos) { - const off_t off = (loff_t) region_offset(LM_DEV_CFG_REG_IDX); + const off_t off = (loff_t) region_to_offset(LM_DEV_CFG_REG_IDX); return pos - off >= 0 && pos - off < PCI_STD_HEADER_SIZEOF; } diff --git a/lib/muser.h b/lib/muser.h index ac31a2e..0a3432a 100644 --- a/lib/muser.h +++ b/lib/muser.h @@ -402,16 +402,14 @@ lm_unmap_sg(lm_ctx_t * const lm_ctx, const dma_sg_t * sg, * Returns the PCI region given the position and size of an address span in the * PCI configuration space. * - * @lm_ctx: the libmuser context * @pos: offset of the address span * @count: size of the address span * @off: output parameter that receives the relative offset within the region. * - * Returns the PCI region (LM_DEV_XXX_REG_IDX), or -1 on error. Sets errno. + * Returns the PCI region (LM_DEV_XXX_REG_IDX), or -errno on error. */ int -lm_get_region(lm_ctx_t * const lm_ctx, const loff_t pos, - const size_t count, loff_t * const off); +lm_get_region(const loff_t pos, const size_t count, loff_t * const off); /* * Advanced stuff. diff --git a/lib/muser_priv.h b/lib/muser_priv.h index 4df8b25..e5af663 100644 --- a/lib/muser_priv.h +++ b/lib/muser_priv.h @@ -7,5 +7,5 @@ muser_pci_hdr_access(lm_ctx_t * const lm_ctx, size_t * const count, lm_reg_info_t *lm_get_region_info(lm_ctx_t * const lm_ctx); -uint64_t region_offset(const uint32_t region); +uint64_t region_to_offset(const uint32_t region); -- cgit v1.1