Messages in this thread | | | Date | Tue, 25 Jun 2019 09:20:59 +0800 | From | Herbert Xu <> | Subject | Re: [PATCH v4 1/4] lib/scatterlist: Fix mapping iterator when sg->offset is greater than PAGE_SIZE |
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On Mon, Jun 24, 2019 at 08:35:33PM +0300, Imre Deak wrote: > Hi, > > On Thu, Jun 20, 2019 at 02:02:21PM +0800, Herbert Xu wrote: > > On Mon, Jun 17, 2019 at 09:15:02PM +0000, Christophe Leroy wrote: > > > All mapping iterator logic is based on the assumption that sg->offset > > > is always lower than PAGE_SIZE. > > > > > > But there are situations where sg->offset is such that the SG item > > > is on the second page. > > could you explain how sg->offset becomes >= PAGE_SIZE?
The network stack can produce SG list elements that are longer than PAGE_SIZE. If you the iterate over it one page at a time then the offset can exceed PAGE_SIZE.
Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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