diff options
author | Frank Haverkamp <haver@linux.vnet.ibm.com> | 2014-03-20 18:11:05 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-16 23:12:39 +0400 |
commit | 718f762efc454796d02f172a929d051f2d6ec01a (patch) | |
tree | 13d8f9558b39963356082460de3ee6855454d972 /drivers/misc | |
parent | ebb2c96bb9214ba38c7fe35d5d725f6e7cb3bbc8 (diff) |
GenWQE: Fix multithreading problems
When being used in a multithreaded application there were problems
with memory pages/cachelines accessed by multiple threads/cpus at the
same time, while doing DMA transfers to/from those. To avoid such
situations this fix is creating a copy of the first and the last page
if it is not fully used. The data is copied from user-space into those
pages and results are copied back when the DDCB-request is
successfully finished.
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r-- | drivers/misc/genwqe/card_base.h | 58 | ||||
-rw-r--r-- | drivers/misc/genwqe/card_dev.c | 38 | ||||
-rw-r--r-- | drivers/misc/genwqe/card_utils.c | 170 |
3 files changed, 180 insertions, 86 deletions
diff --git a/drivers/misc/genwqe/card_base.h b/drivers/misc/genwqe/card_base.h index 5e4dbd21f89a..0e608a288603 100644 --- a/drivers/misc/genwqe/card_base.h +++ b/drivers/misc/genwqe/card_base.h @@ -337,6 +337,44 @@ enum genwqe_requ_state { }; /** + * struct genwqe_sgl - Scatter gather list describing user-space memory + * @sgl: scatter gather list needs to be 128 byte aligned + * @sgl_dma_addr: dma address of sgl + * @sgl_size: size of area used for sgl + * @user_addr: user-space address of memory area + * @user_size: size of user-space memory area + * @page: buffer for partial pages if needed + * @page_dma_addr: dma address partial pages + */ +struct genwqe_sgl { + dma_addr_t sgl_dma_addr; + struct sg_entry *sgl; + size_t sgl_size; /* size of sgl */ + + void __user *user_addr; /* user-space base-address */ + size_t user_size; /* size of memory area */ + + unsigned long nr_pages; + unsigned long fpage_offs; + size_t fpage_size; + size_t lpage_size; + + void *fpage; + dma_addr_t fpage_dma_addr; + + void *lpage; + dma_addr_t lpage_dma_addr; +}; + +int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl, + void __user *user_addr, size_t user_size); + +int genwqe_setup_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl, + dma_addr_t *dma_list); + +int genwqe_free_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl); + +/** * struct ddcb_requ - Kernel internal representation of the DDCB request * @cmd: User space representation of the DDCB execution request */ @@ -347,9 +385,7 @@ struct ddcb_requ { struct ddcb_queue *queue; /* associated queue */ struct dma_mapping dma_mappings[DDCB_FIXUPS]; - struct sg_entry *sgl[DDCB_FIXUPS]; - dma_addr_t sgl_dma_addr[DDCB_FIXUPS]; - size_t sgl_size[DDCB_FIXUPS]; + struct genwqe_sgl sgls[DDCB_FIXUPS]; /* kernel/user shared content */ struct genwqe_ddcb_cmd cmd; /* ddcb_no for this request */ @@ -453,22 +489,6 @@ int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, int genwqe_user_vunmap(struct genwqe_dev *cd, struct dma_mapping *m, struct ddcb_requ *req); -struct sg_entry *genwqe_alloc_sgl(struct genwqe_dev *cd, int num_pages, - dma_addr_t *dma_addr, size_t *sgl_size); - -void genwqe_free_sgl(struct genwqe_dev *cd, struct sg_entry *sg_list, - dma_addr_t dma_addr, size_t size); - -int genwqe_setup_sgl(struct genwqe_dev *cd, - unsigned long offs, - unsigned long size, - struct sg_entry *sgl, /* genwqe sgl */ - dma_addr_t dma_addr, size_t sgl_size, - dma_addr_t *dma_list, int page_offs, int num_pages); - -int genwqe_check_sgl(struct genwqe_dev *cd, struct sg_entry *sg_list, - int size); - static inline bool dma_mapping_used(struct dma_mapping *m) { if (!m) diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c index 0d05ca77c458..1d2f163a1906 100644 --- a/drivers/misc/genwqe/card_dev.c +++ b/drivers/misc/genwqe/card_dev.c @@ -840,15 +840,8 @@ static int ddcb_cmd_cleanup(struct genwqe_file *cfile, struct ddcb_requ *req) __genwqe_del_mapping(cfile, dma_map); genwqe_user_vunmap(cd, dma_map, req); } - if (req->sgl[i] != NULL) { - genwqe_free_sgl(cd, req->sgl[i], - req->sgl_dma_addr[i], - req->sgl_size[i]); - req->sgl[i] = NULL; - req->sgl_dma_addr[i] = 0x0; - req->sgl_size[i] = 0; - } - + if (req->sgls[i].sgl != NULL) + genwqe_free_sync_sgl(cd, &req->sgls[i]); } return 0; } @@ -917,7 +910,7 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req) case ATS_TYPE_SGL_RDWR: case ATS_TYPE_SGL_RD: { - int page_offs, nr_pages, offs; + int page_offs; u_addr = be64_to_cpu(*((__be64 *) &cmd->asiv[asiv_offs])); @@ -955,27 +948,18 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req) page_offs = 0; } - offs = offset_in_page(u_addr); - nr_pages = DIV_ROUND_UP(offs + u_size, PAGE_SIZE); - /* create genwqe style scatter gather list */ - req->sgl[i] = genwqe_alloc_sgl(cd, m->nr_pages, - &req->sgl_dma_addr[i], - &req->sgl_size[i]); - if (req->sgl[i] == NULL) { - rc = -ENOMEM; + rc = genwqe_alloc_sync_sgl(cd, &req->sgls[i], + (void __user *)u_addr, + u_size); + if (rc != 0) goto err_out; - } - genwqe_setup_sgl(cd, offs, u_size, - req->sgl[i], - req->sgl_dma_addr[i], - req->sgl_size[i], - m->dma_list, - page_offs, - nr_pages); + + genwqe_setup_sgl(cd, &req->sgls[i], + &m->dma_list[page_offs]); *((__be64 *)&cmd->asiv[asiv_offs]) = - cpu_to_be64(req->sgl_dma_addr[i]); + cpu_to_be64(req->sgls[i].sgl_dma_addr); break; } diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c index 6b1a6ef9f1a8..d049d271699c 100644 --- a/drivers/misc/genwqe/card_utils.c +++ b/drivers/misc/genwqe/card_utils.c @@ -275,67 +275,107 @@ static int genwqe_sgl_size(int num_pages) return roundup(len, PAGE_SIZE); } -struct sg_entry *genwqe_alloc_sgl(struct genwqe_dev *cd, int num_pages, - dma_addr_t *dma_addr, size_t *sgl_size) +/** + * genwqe_alloc_sync_sgl() - Allocate memory for sgl and overlapping pages + * + * Allocates memory for sgl and overlapping pages. Pages which might + * overlap other user-space memory blocks are being cached for DMAs, + * such that we do not run into syncronization issues. Data is copied + * from user-space into the cached pages. + */ +int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl, + void __user *user_addr, size_t user_size) { + int rc; struct pci_dev *pci_dev = cd->pci_dev; - struct sg_entry *sgl; - *sgl_size = genwqe_sgl_size(num_pages); - if (get_order(*sgl_size) > MAX_ORDER) { + sgl->fpage_offs = offset_in_page((unsigned long)user_addr); + sgl->fpage_size = min_t(size_t, PAGE_SIZE-sgl->fpage_offs, user_size); + sgl->nr_pages = DIV_ROUND_UP(sgl->fpage_offs + user_size, PAGE_SIZE); + sgl->lpage_size = (user_size - sgl->fpage_size) % PAGE_SIZE; + + dev_dbg(&pci_dev->dev, "[%s] uaddr=%p usize=%8ld nr_pages=%ld " + "fpage_offs=%lx fpage_size=%ld lpage_size=%ld\n", + __func__, user_addr, user_size, sgl->nr_pages, + sgl->fpage_offs, sgl->fpage_size, sgl->lpage_size); + + sgl->user_addr = user_addr; + sgl->user_size = user_size; + sgl->sgl_size = genwqe_sgl_size(sgl->nr_pages); + + if (get_order(sgl->sgl_size) > MAX_ORDER) { dev_err(&pci_dev->dev, "[%s] err: too much memory requested!\n", __func__); - return NULL; + return -ENOMEM; } - sgl = __genwqe_alloc_consistent(cd, *sgl_size, dma_addr); - if (sgl == NULL) { + sgl->sgl = __genwqe_alloc_consistent(cd, sgl->sgl_size, + &sgl->sgl_dma_addr); + if (sgl->sgl == NULL) { dev_err(&pci_dev->dev, "[%s] err: no memory available!\n", __func__); - return NULL; + return -ENOMEM; } - return sgl; + /* Only use buffering on incomplete pages */ + if ((sgl->fpage_size != 0) && (sgl->fpage_size != PAGE_SIZE)) { + sgl->fpage = __genwqe_alloc_consistent(cd, PAGE_SIZE, + &sgl->fpage_dma_addr); + if (sgl->fpage == NULL) + goto err_out; + + /* Sync with user memory */ + if (copy_from_user(sgl->fpage + sgl->fpage_offs, + user_addr, sgl->fpage_size)) { + rc = -EFAULT; + goto err_out; + } + } + if (sgl->lpage_size != 0) { + sgl->lpage = __genwqe_alloc_consistent(cd, PAGE_SIZE, + &sgl->lpage_dma_addr); + if (sgl->lpage == NULL) + goto err_out1; + + /* Sync with user memory */ + if (copy_from_user(sgl->lpage, user_addr + user_size - + sgl->lpage_size, sgl->lpage_size)) { + rc = -EFAULT; + goto err_out1; + } + } + return 0; + + err_out1: + __genwqe_free_consistent(cd, PAGE_SIZE, sgl->fpage, + sgl->fpage_dma_addr); + err_out: + __genwqe_free_consistent(cd, sgl->sgl_size, sgl->sgl, + sgl->sgl_dma_addr); + return -ENOMEM; } -int genwqe_setup_sgl(struct genwqe_dev *cd, - unsigned long offs, - unsigned long size, - struct sg_entry *sgl, - dma_addr_t dma_addr, size_t sgl_size, - dma_addr_t *dma_list, int page_offs, int num_pages) +int genwqe_setup_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl, + dma_addr_t *dma_list) { int i = 0, j = 0, p; unsigned long dma_offs, map_offs; - struct pci_dev *pci_dev = cd->pci_dev; dma_addr_t prev_daddr = 0; struct sg_entry *s, *last_s = NULL; - - /* sanity checks */ - if (offs > PAGE_SIZE) { - dev_err(&pci_dev->dev, - "[%s] too large start offs %08lx\n", __func__, offs); - return -EFAULT; - } - if (sgl_size < genwqe_sgl_size(num_pages)) { - dev_err(&pci_dev->dev, - "[%s] sgl_size too small %08lx for %d pages\n", - __func__, sgl_size, num_pages); - return -EFAULT; - } + size_t size = sgl->user_size; dma_offs = 128; /* next block if needed/dma_offset */ - map_offs = offs; /* offset in first page */ + map_offs = sgl->fpage_offs; /* offset in first page */ - s = &sgl[0]; /* first set of 8 entries */ + s = &sgl->sgl[0]; /* first set of 8 entries */ p = 0; /* page */ - while (p < num_pages) { + while (p < sgl->nr_pages) { dma_addr_t daddr; unsigned int size_to_map; /* always write the chaining entry, cleanup is done later */ j = 0; - s[j].target_addr = cpu_to_be64(dma_addr + dma_offs); + s[j].target_addr = cpu_to_be64(sgl->sgl_dma_addr + dma_offs); s[j].len = cpu_to_be32(128); s[j].flags = cpu_to_be32(SG_CHAINED); j++; @@ -343,7 +383,17 @@ int genwqe_setup_sgl(struct genwqe_dev *cd, while (j < 8) { /* DMA mapping for requested page, offs, size */ size_to_map = min(size, PAGE_SIZE - map_offs); - daddr = dma_list[page_offs + p] + map_offs; + + if ((p == 0) && (sgl->fpage != NULL)) { + daddr = sgl->fpage_dma_addr + map_offs; + + } else if ((p == sgl->nr_pages - 1) && + (sgl->lpage != NULL)) { + daddr = sgl->lpage_dma_addr; + } else { + daddr = dma_list[p] + map_offs; + } + size -= size_to_map; map_offs = 0; @@ -358,7 +408,7 @@ int genwqe_setup_sgl(struct genwqe_dev *cd, size_to_map); p++; /* process next page */ - if (p == num_pages) + if (p == sgl->nr_pages) goto fixup; /* nothing to do */ prev_daddr = daddr + size_to_map; @@ -374,7 +424,7 @@ int genwqe_setup_sgl(struct genwqe_dev *cd, j++; p++; /* process next page */ - if (p == num_pages) + if (p == sgl->nr_pages) goto fixup; /* nothing to do */ } dma_offs += 128; @@ -395,10 +445,50 @@ int genwqe_setup_sgl(struct genwqe_dev *cd, return 0; } -void genwqe_free_sgl(struct genwqe_dev *cd, struct sg_entry *sg_list, - dma_addr_t dma_addr, size_t size) +/** + * genwqe_free_sync_sgl() - Free memory for sgl and overlapping pages + * + * After the DMA transfer has been completed we free the memory for + * the sgl and the cached pages. Data is being transfered from cached + * pages into user-space buffers. + */ +int genwqe_free_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl) { - __genwqe_free_consistent(cd, size, sg_list, dma_addr); + int rc; + struct pci_dev *pci_dev = cd->pci_dev; + + if (sgl->fpage) { + if (copy_to_user(sgl->user_addr, sgl->fpage + sgl->fpage_offs, + sgl->fpage_size)) { + dev_err(&pci_dev->dev, "[%s] err: copying fpage!\n", + __func__); + rc = -EFAULT; + } + __genwqe_free_consistent(cd, PAGE_SIZE, sgl->fpage, + sgl->fpage_dma_addr); + sgl->fpage = NULL; + sgl->fpage_dma_addr = 0; + } + if (sgl->lpage) { + if (copy_to_user(sgl->user_addr + sgl->user_size - + sgl->lpage_size, sgl->lpage, + sgl->lpage_size)) { + dev_err(&pci_dev->dev, "[%s] err: copying lpage!\n", + __func__); + rc = -EFAULT; + } + __genwqe_free_consistent(cd, PAGE_SIZE, sgl->lpage, + sgl->lpage_dma_addr); + sgl->lpage = NULL; + sgl->lpage_dma_addr = 0; + } + __genwqe_free_consistent(cd, sgl->sgl_size, sgl->sgl, + sgl->sgl_dma_addr); + + sgl->sgl = NULL; + sgl->sgl_dma_addr = 0x0; + sgl->sgl_size = 0; + return rc; } /** |