iscsitarget: resolve build error with linux kernel 4.3 and above

1. test_bit was used to return true boolean value, if
   BIO_UPTODATE bit of bio->bi_flags is set. But the same
   job can be done by checking bio->bi_error, implemented in
   linux kernel 4.3 and above. If bio->bi_error is set, then
   it denotes error.

Ref: https://github.com/torvalds/linux/commit/4246a0b63bd8f56a1469b12eafeb875b1041a451

It solves below build error:
-- snip --
iscsitarget-1.4.20.3+svn502/kernel/block-io.c:40:19: error: 'BIO_UPTODATE' undeclared (first use in this function)
   error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? error : -EIO;
-- CUT --

2. bio can always be filled to a maximum value of BIO_MAX_PAGES,
   so no need to check for min value for linux kernel 4.3 and above.

Ref: https://github.com/torvalds/linux/commit/b54ffb73cadcdcff9cc1ae0e11f502407e3e2e4c

It solves below build error:
-- snip --
iscsitarget-1.4.20.3+svn502/kernel/block-io.c:80:15: error: implicit declaration of function 'bio_get_nr_vecs' [-Werror=implicit-function-declaration]
    max_pages = bio_get_nr_vecs(bio_data->bdev);
-- CUT --

3. Remove unwanted explicit setting of CFLAGS and CC flags. Setting them in
   oe_runmake command, will override CFLAGS mentioned in iscsitarget Makefile
   and resulting in a below error:

-- snip --
 In file included from iscsid.c:38:0:
 iscsid.h:38:19: fatal error: iet_u.h: No such file or directory
 compilation terminated.
 In file included from conn.c:15:0:
 iscsid.h:38:19: fatal error: iet_u.h: No such file or directory
 compilation terminated.
-- CUT --

Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/meta-networking/recipes-extended/iscsitarget/files/build_with_updated_bio_struct_of_linux_v4.3_and_above.patch b/meta-networking/recipes-extended/iscsitarget/files/build_with_updated_bio_struct_of_linux_v4.3_and_above.patch
new file mode 100644
index 000000000..0e8b792af
--- /dev/null
+++ b/meta-networking/recipes-extended/iscsitarget/files/build_with_updated_bio_struct_of_linux_v4.3_and_above.patch
@@ -0,0 +1,75 @@
+1. test_bit was used to return true boolean value, if
+   BIO_UPTODATE bit of bio->bi_flags is set. But the same
+   job can be done by checking bio->bi_error, implemented in
+   linux kernel 4.3 and above. If bio->bi_error is set, then 
+   it denotes error.
+
+Ref: https://github.com/torvalds/linux/commit/4246a0b63bd8f56a1469b12eafeb875b1041a451
+
+It solves below build error:
+-- snip --
+iscsitarget-1.4.20.3+svn502/kernel/block-io.c:40:19: error: 'BIO_UPTODATE' undeclared (first use in this function)
+   error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? error : -EIO;
+-- CUT --
+
+2. bio can always be filled to a maximum value of BIO_MAX_PAGES, 
+   so no need to check for min value for linux kernel 4.3 and above.
+
+Ref: https://github.com/torvalds/linux/commit/b54ffb73cadcdcff9cc1ae0e11f502407e3e2e4c
+
+It solves below build error:
+-- snip --
+iscsitarget-1.4.20.3+svn502/kernel/block-io.c:80:15: error: implicit declaration of function 'bio_get_nr_vecs' [-Werror=implicit-function-declaration]
+    max_pages = bio_get_nr_vecs(bio_data->bdev);
+-- CUT --
+
+Upstream-Status: Pending
+
+Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
+
+diff -Naurp iscsitarget-1.4.20.3+svn502_org/kernel/block-io.c iscsitarget-1.4.20.3+svn502/kernel/block-io.c
+--- iscsitarget-1.4.20.3+svn502_org/kernel/block-io.c   2016-04-01 09:07:12.891810059 +0530
++++ iscsitarget-1.4.20.3+svn502/kernel/block-io.c       2016-04-01 09:15:59.076469313 +0530
+@@ -33,7 +33,11 @@ static void blockio_bio_endio(struct bio
+ {
+        struct tio_work *tio_work = bio->bi_private;
+ 
++#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
++       error = bio->bi_error ? -EIO : error;
++#else
+        error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? error : -EIO;
++#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0) */     
+ 
+        if (error)
+                atomic_set(&tio_work->error, error);
+@@ -61,6 +65,10 @@ blockio_make_request(struct iet_volume *
+        u32 size = tio->size;
+        u32 tio_index = 0;
+ 
++#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
++       int err = 0;
++       loff_t ppos = tio->offset;      
++#else  
+        int max_pages = 1;
+        int err = 0;
+ 
+@@ -69,6 +77,7 @@ blockio_make_request(struct iet_volume *
+        /* Calculate max_pages for bio_alloc (memory saver) */
+        if (bdev_q)
+                max_pages = bio_get_nr_vecs(bio_data->bdev);
++#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0) */
+ 
+        tio_work = kzalloc(sizeof (*tio_work), GFP_KERNEL);
+        if (!tio_work)
+@@ -80,7 +89,11 @@ blockio_make_request(struct iet_volume *
+ 
+        /* Main processing loop, allocate and fill all bios */
+        while (size && tio_index < tio->pg_cnt) {
++#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
++               bio = bio_alloc(GFP_KERNEL, BIO_MAX_PAGES);
++#else                  
+                bio = bio_alloc(GFP_KERNEL, min(max_pages, BIO_MAX_PAGES));
++#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0) */             
+                if (!bio) {
+                        err = -ENOMEM;
+                        goto out;