msm: kgsl: Restrict the maximum memory entries for bulk cache sync

Restrict the maximum number of memory entries that can be specified
to a single bulk cache sync call to PAGE_SIZE / sizeof(unsigned int)
so that the allocation can always fit within one page.

CRs-fixed: 578062
Change-Id: Ic0dedbad07e1986cd6ccc5b260ffef82b5adb6d3
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
msm: kgsl: Protect against a potential overflow in kgsl_sg_alloc

Avoid allocating a scatterlist so large that it overflows the size
passed to the memory allocators.

CRs-fixed: 564448
Change-Id: Ic0dedbad2ab421ddec8f3be38d61c9bdf9ae5bd4
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
msm: kgsl: avoid zero length scatterlist allocation

During sglist allocation we calculate sglen as
per below

sglen_alloc = PAGE_ALIGN(size) >> PAGE_SHIFT;

sglen_alloc can be zero if size falls within the
last page. For example, when size = 0xFFFF_FF7B,
PAGE_ALIGN(0xFFFF_FF7B) will be 0, considering
0x1000 (4kb) PAGE_SIZE. if kzalloc() with
zero size, it will return ZERO_SIZE_PTR which is
not NULL and we always do NULL check. Dereferencing
ZERO_SIZE_PTR will lead to a distinct access fault.

Change-Id: Ibcc6198438c13b5111be0faa736328db92511597
CRs-Fixed: 563106
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>
msm: kgsl: Fix several possible problem spots in the dispatcher

Fix a few spots that the compiler warnings missed. Avoid
dereferencing a pointer that may have returned ERR_PTR() without
first checking to see that if it did return ERR_PTR() and correct
an egregious signed / unsigned mixup. Not sure why the compiler
didn't yell at me for that one.

Change-Id: Ic0dedbadf075b34e51a89ce625d2308c5171a58d
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>