nvmet-rdma: handle inline data with a nonzero offset

nvmet-rdma: handle inline data with a nonzero offset

nvmet_rdma_use_inline_sg() maps the host-controlled inline data offset
into the per-command inline scatterlist.  The bounds check admits any
offset with off + len <= inline_data_size, but the mapping still assumes
the data begins in the first inline page:

	sg->offset = off;
	sg->length = min_t(int, len, PAGE_SIZE - off);

When a port is configured with inline_data_size > PAGE_SIZE (settable up
to max(SZ_16K, PAGE_SIZE)), an offset in (PAGE_SIZE, inline_data_size]
makes "PAGE_SIZE - off" underflow, so sg->length is set to ~4 GiB and
the block backend reads far past the first inline page.  num_pages(len)
also ignores the offset, so an in-bounds offset whose [off, off+len)
span crosses a page boundary under-counts the scatterlist.

Map the offset properly: split it into a page index and an in-page
offset, start the scatterlist at that page, and size the page count from
page_off + len.  Because the request scatterlist may now start at
inline_sg[page_idx] rather than inline_sg[0], generalize the inline-SGL
identity test in nvmet_rdma_release_rsp() to a range test; otherwise the
persistent inline scatterlist is mistaken for an allocated one and
nvmet_req_free_sgls() frees an inline page (and warns in
free_large_kmalloc()).

Fixes: 0d5ee2b2ab4f ("nvmet-rdma: support max(16KB, PAGE_SIZE) inline data")
Cc: stable@vger.kernel.org
Suggested-by: Keith Busch <kbusch@kernel.org>
Reported-by: Bryam Vargas <hexlabsecurity@proton.me>
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>