5.15-stable review patch. If anyone has any objections, please let me know.
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From: Johannes Berg johannes.berg@intel.com
[ Upstream commit 7774e3920029398ad49dc848b23840593f14d515 ]
The firmware dumps can be pretty big, and since we use single pages for each SG table entry, even the table itself may end up being an order-5 allocation. Build chained tables so that we need not allocate a higher-order table here.
This could be improved and cleaned up, e.g. by using the SG pool code or simply kvmalloc(), but all of that would require also updating the devcoredump first since that frees it all, so we need to be more careful. SG pool might also run against the CONFIG_ARCH_NO_SG_CHAIN limitation, which is irrelevant here.
Also use _devcd_free_sgtable() for the error paths now, much simpler especially since it's in two places now.
Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Miri Korenblit miriam.rachel.korenblit@intel.com Link: https://patch.msgid.link/20250209143303.697c7a465ac9.Iea982df46b5c075bfb77ad... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/intel/iwlwifi/fw/dbg.c | 86 ++++++++++++++------- 1 file changed, 58 insertions(+), 28 deletions(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/dbg.c b/drivers/net/wireless/intel/iwlwifi/fw/dbg.c index fc630a0d9c83c..f1d07ddb3f831 100644 --- a/drivers/net/wireless/intel/iwlwifi/fw/dbg.c +++ b/drivers/net/wireless/intel/iwlwifi/fw/dbg.c @@ -558,41 +558,71 @@ static void iwl_dump_prph(struct iwl_fw_runtime *fwrt, }
/* - * alloc_sgtable - allocates scallerlist table in the given size, - * fills it with pages and returns it + * alloc_sgtable - allocates (chained) scatterlist in the given size, + * fills it with pages and returns it * @size: the size (in bytes) of the table -*/ -static struct scatterlist *alloc_sgtable(int size) + */ +static struct scatterlist *alloc_sgtable(ssize_t size) { - int alloc_size, nents, i; - struct page *new_page; - struct scatterlist *iter; - struct scatterlist *table; + struct scatterlist *result = NULL, *prev; + int nents, i, n_prev;
nents = DIV_ROUND_UP(size, PAGE_SIZE); - table = kcalloc(nents, sizeof(*table), GFP_KERNEL); - if (!table) - return NULL; - sg_init_table(table, nents); - iter = table; - for_each_sg(table, iter, sg_nents(table), i) { - new_page = alloc_page(GFP_KERNEL); - if (!new_page) { - /* release all previous allocated pages in the table */ - iter = table; - for_each_sg(table, iter, sg_nents(table), i) { - new_page = sg_page(iter); - if (new_page) - __free_page(new_page); - } - kfree(table); + +#define N_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(*result)) + /* + * We need an additional entry for table chaining, + * this ensures the loop can finish i.e. we can + * fit at least two entries per page (obviously, + * many more really fit.) + */ + BUILD_BUG_ON(N_ENTRIES_PER_PAGE < 2); + + while (nents > 0) { + struct scatterlist *new, *iter; + int n_fill, n_alloc; + + if (nents <= N_ENTRIES_PER_PAGE) { + /* last needed table */ + n_fill = nents; + n_alloc = nents; + nents = 0; + } else { + /* fill a page with entries */ + n_alloc = N_ENTRIES_PER_PAGE; + /* reserve one for chaining */ + n_fill = n_alloc - 1; + nents -= n_fill; + } + + new = kcalloc(n_alloc, sizeof(*new), GFP_KERNEL); + if (!new) { + if (result) + _devcd_free_sgtable(result); return NULL; } - alloc_size = min_t(int, size, PAGE_SIZE); - size -= PAGE_SIZE; - sg_set_page(iter, new_page, alloc_size, 0); + sg_init_table(new, n_alloc); + + if (!result) + result = new; + else + sg_chain(prev, n_prev, new); + prev = new; + n_prev = n_alloc; + + for_each_sg(new, iter, n_fill, i) { + struct page *new_page = alloc_page(GFP_KERNEL); + + if (!new_page) { + _devcd_free_sgtable(result); + return NULL; + } + + sg_set_page(iter, new_page, PAGE_SIZE, 0); + } } - return table; + + return result; }
static void iwl_fw_get_prph_len(struct iwl_fw_runtime *fwrt,