diff options
| -rw-r--r-- | arch/powerpc/perf/hv-24x7.c | 101 |
1 files changed, 14 insertions, 87 deletions
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 697759d8eb1..6c8710dd90c 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -75,86 +75,6 @@ static struct attribute_group format_group = { static struct kmem_cache *hv_page_cache; -/* - * read_offset_data - copy data from one buffer to another while treating the - * source buffer as a small view on the total avaliable - * source data. - * - * @dest: buffer to copy into - * @dest_len: length of @dest in bytes - * @requested_offset: the offset within the source data we want. Must be > 0 - * @src: buffer to copy data from - * @src_len: length of @src in bytes - * @source_offset: the offset in the sorce data that (src,src_len) refers to. - * Must be > 0 - * - * returns the number of bytes copied. - * - * The following ascii art shows the various buffer possitioning we need to - * handle, assigns some arbitrary varibles to points on the buffer, and then - * shows how we fiddle with those values to get things we care about (copy - * start in src and copy len) - * - * s = @src buffer - * d = @dest buffer - * '.' areas in d are written to. - * - * u - * x w v z - * d |.........| - * s |----------------------| - * - * u - * x w z v - * d |........------| - * s |------------------| - * - * x w u,z,v - * d |........| - * s |------------------| - * - * x,w u,v,z - * d |..................| - * s |------------------| - * - * x u - * w v z - * d |........| - * s |------------------| - * - * x z w v - * d |------| - * s |------| - * - * x = source_offset - * w = requested_offset - * z = source_offset + src_len - * v = requested_offset + dest_len - * - * w_offset_in_s = w - x = requested_offset - source_offset - * z_offset_in_s = z - x = src_len - * v_offset_in_s = v - x = request_offset + dest_len - src_len - */ -static ssize_t read_offset_data(void *dest, size_t dest_len, - loff_t requested_offset, void *src, - size_t src_len, loff_t source_offset) -{ - size_t w_offset_in_s = requested_offset - source_offset; - size_t z_offset_in_s = src_len; - size_t v_offset_in_s = requested_offset + dest_len - src_len; - size_t u_offset_in_s = min(z_offset_in_s, v_offset_in_s); - size_t copy_len = u_offset_in_s - w_offset_in_s; - - if (requested_offset < 0 || source_offset < 0) - return -EINVAL; - - if (z_offset_in_s <= w_offset_in_s) - return 0; - - memcpy(dest, src + w_offset_in_s, copy_len); - return copy_len; -} - static unsigned long h_get_24x7_catalog_page_(unsigned long phys_4096, unsigned long version, unsigned long index) @@ -183,8 +103,10 @@ static ssize_t catalog_read(struct file *filp, struct kobject *kobj, { unsigned long hret; ssize_t ret = 0; - size_t catalog_len = 0, catalog_page_len = 0, page_count = 0; + size_t catalog_len = 0, catalog_page_len = 0; loff_t page_offset = 0; + loff_t offset_in_page; + size_t copy_len; uint64_t catalog_version_num = 0; void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); struct hv_24x7_catalog_page_0 *page_0 = page; @@ -202,7 +124,7 @@ static ssize_t catalog_read(struct file *filp, struct kobject *kobj, catalog_len = catalog_page_len * 4096; page_offset = offset / 4096; - page_count = count / 4096; + offset_in_page = offset % 4096; if (page_offset >= catalog_page_len) goto e_free; @@ -216,8 +138,13 @@ static ssize_t catalog_read(struct file *filp, struct kobject *kobj, } } - ret = read_offset_data(buf, count, offset, - page, 4096, page_offset * 4096); + copy_len = 4096 - offset_in_page; + if (copy_len > count) + copy_len = count; + + memcpy(buf, page+offset_in_page, copy_len); + ret = copy_len; + e_free: if (hret) pr_err("h_get_24x7_catalog_page(ver=%lld, page=%lld) failed:" @@ -225,9 +152,9 @@ e_free: catalog_version_num, page_offset, hret); kmem_cache_free(hv_page_cache, page); - pr_devel("catalog_read: offset=%lld(%lld) count=%zu(%zu) catalog_len=%zu(%zu) => %zd\n", - offset, page_offset, count, page_count, catalog_len, - catalog_page_len, ret); + pr_devel("catalog_read: offset=%lld(%lld) count=%zu " + "catalog_len=%zu(%zu) => %zd\n", offset, page_offset, + count, catalog_len, catalog_page_len, ret); return ret; } |