[net-next,v3,0/3] Use new for_each macro to create hexdumps

Message

Nick Child Feb. 19, 2025, 9:10 p.m. UTC

Currently, obtaining a hexdump can be done through one of the following:
 1. hex_dump_to_buffer - takes at most 32 bytes of a buffer and returns a 
     hexdump string representation
 2. print_hex_dump - prints output of hex_dump_to_buffer iteratively over
    a large buffer

There is no functionality for iterating over a large buffer and receiving
the string representation. It seems most users of hex_dump_to_buffer are
calling hex_dump_to_buffer within the body of a loop which iterates
through a buffer.

This patchset creates a for_each macro that accepts a buffer and fills
out an output string with the converted hexdump. This loops over the
buffer and takes care of incrementing pointers. Hopefully this makes
writing sequential calls to hex_dump_to_buffer more straightforward.

From a users perspective there should be no difference in output.

The inspiration here was I wanted to use print_hex_dump in ibmvnic code
but I wanted to print through netdevice printing functions to maintain
formatting. Looking at other users of hex_dump_to_buffer it seems they had
similar intentions.

Thanks to Dave, Simon, David, and Paolo for v2 review.

Changes since v2:
 - patch1: remove unnecssary call to min, this addresses Simon's observation of
 gcc-7.5.0 warning. Other possible solutions were to change typing but it turns
 out the call to min is unnecessary since hex_dump_to_buffer has logic for
 handling len > rowlen and vice versa. So we can be honest about the len.
 - patch1: cleanup for loop i increment in response to Dave's review
 - patch3: fix ordering of [Signed-off,Reviewed]-by tags in the commit message
 - target net-next thanks to Paolo's recommendation

v2: https://lore.kernel.org/lkml/[e-mail]/

Changes since v1:
 - add Jacob's Reviewed-by
 - fix kernel doc typo in patch 1 noted by Simon

v1: https://lore.kernel.org/lkml/[e-mail]/

similar intentions.
Nick Child (3):
  hexdump: Implement macro for converting large buffers
  hexdump: Use for_each macro in print_hex_dump
  ibmvnic: Print data buffers with kernel API's

 drivers/net/ethernet/ibm/ibmvnic.c | 23 ++++++++++++++---------
 include/linux/printk.h             | 20 ++++++++++++++++++++
 lib/hexdump.c                      | 11 +++--------
 3 files changed, 37 insertions(+), 17 deletions(-)