From 7b7f2bdf829ecf21845c0a571847ea18c6934970 Mon Sep 17 00:00:00 2001 From: Long Li Date: Wed, 30 May 2018 12:47:58 -0700 Subject: [PATCH] CIFS: Introduce helper function to get page offset and length in smb_rqst Introduce a function rqst_page_get_length to return the page offset and length for a given page in smb_rqst. This function is to be used by following patches. Signed-off-by: Long Li Signed-off-by: Steve French --- fs/cifs/cifsproto.h | 3 +++ fs/cifs/misc.c | 17 +++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index 7f0c773d5f6b..84765c8764bf 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -557,4 +557,7 @@ int cifs_alloc_hash(const char *name, struct crypto_shash **shash, struct sdesc **sdesc); void cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc); +extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page, + unsigned int *len, unsigned int *offset); + #endif /* _CIFSPROTO_H */ diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index aba3fc3058da..f90d4ad6624c 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -905,3 +905,20 @@ cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc) crypto_free_shash(*shash); *shash = NULL; } + +/** + * rqst_page_get_length - obtain the length and offset for a page in smb_rqst + * Input: rqst - a smb_rqst, page - a page index for rqst + * Output: *len - the length for this page, *offset - the offset for this page + */ +void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page, + unsigned int *len, unsigned int *offset) +{ + *len = rqst->rq_pagesz; + *offset = (page == 0) ? rqst->rq_offset : 0; + + if (rqst->rq_npages == 1 || page == rqst->rq_npages-1) + *len = rqst->rq_tailsz; + else if (page == 0) + *len = rqst->rq_pagesz - rqst->rq_offset; +}