Messages in this thread | | | Subject | Re: [PATCH 3/6] lib/scatterlist: Do not leak pages when high-order allocation fails | From | Tvrtko Ursulin <> | Date | Wed, 7 Mar 2018 17:06:55 +0000 |
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On 07/03/18 16:16, Bart Van Assche wrote: > On Wed, 2018-03-07 at 12:47 +0000, Tvrtko Ursulin wrote: >> diff --git a/lib/scatterlist.c b/lib/scatterlist.c >> index 9884be50a2c0..e13a759c5c49 100644 >> --- a/lib/scatterlist.c >> +++ b/lib/scatterlist.c >> @@ -493,7 +493,7 @@ struct scatterlist *sgl_alloc_order(unsigned long length, unsigned int order, >> { >> unsigned int chunk_len = PAGE_SIZE << order; >> struct scatterlist *sgl, *sg; >> - unsigned int nent; >> + unsigned int nent, i; >> >> nent = round_up(length, chunk_len) >> (PAGE_SHIFT + order); >> >> @@ -517,11 +517,12 @@ struct scatterlist *sgl_alloc_order(unsigned long length, unsigned int order, >> >> sg_init_table(sgl, nent); >> sg = sgl; >> + i = 0; >> while (length) { >> struct page *page = alloc_pages(gfp, order); >> >> if (!page) { >> - sgl_free(sgl); >> + sgl_free_n_order(sgl, i, order); >> return NULL; >> } >> >> @@ -529,6 +530,7 @@ struct scatterlist *sgl_alloc_order(unsigned long length, unsigned int order, >> sg_set_page(sg, page, chunk_len, 0); >> length -= chunk_len; >> sg = sg_next(sg); >> + i++; >> } > > Since the entire sg-list is zero-initialized before this loop starts, since > the sg-list is not chained onto another sg-list before this function returns > and since sgl_free_n_order() checks whether or not each page pointer is NULL > before freeing it I think we don't need the new loop variable 'i' and that > we can call sgl_free_order() instead of sgl_free_n_order().
Yes true, I've only realized that in a later patch. Can rebase to move that change earlier in.
Regards,
Tvrtko
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